Spectroscopy - Science method

Thank you for the explanation Abdelhak :)

Auger electrons are associated with EDS, XFS. For all excitation events, there is a partition between Auger electrons and fluorescent photons and depends on the absorption edge and the size of the atom.

As you increase in atomic number (Z), fluorescent yield increases and auger electrons yield decreases.

Auger electrons will be more probably at low energy, and at L-edges (L2,3 < L1). This is why you generally don't see X-ray fluorescence experiments at low energy, but it is possible to generate exceptional spectra using a silicon drift detector (SDD) and I have done many experiments to show this.

Energy dispersive (proportional counters) detectors are not generally utilized in modern XAS experiments any more.

I agree with most of what is posted at Rocky Mountain Labs, but I would say it a bit differently. There are two main areas of difference between the techniques: the excitation and the detectors.

SEM-microanalysis uses the energetic electrons of the beam of the SEM to knock out inner shell electrons from atoms in the sample. As the sample relaxes, i.e., outer shell electrons fall into the vacancies, they can result in the emission of an x-ray photon. Since a focused beam is exciting the sample, it can be used to analyze small volumes (a few um). Since electrons are interacting with the sample, there is also a lot of bremstrallung background.

XRF uses a beam of x-rays to excite the sample. Those x-rays could come from a tube or from a radioactive source. They knock out the same inner shell electrons and x-rays are produced the same way as in the SEM. However, XRF leads to a much lower background. Since detection depends on peak to background ratio, detection is much better. The XRF source is typically much more intense so count rate and detection improve. The down side is that the excitation volume is much larger. Typically the area was several mm across. New systems can reduce that to tens of um, but it is not microscopic.

Detection is a different issue. Both SEM and XRF systems can use either energy-dispersive spectroscopy (based on a Si chip) or wavelength dispersive spectroscopy (based on diffracting crystals) to analyze the x-rays. EDS tends to be cheaper than WDS. It is better suited to weaker signals (as from an SEM), but it has less energy resolution than WDS.

Therefore, it depends on your requirements.

Have you been able to solve the problem?

Dear Nina,

From powder samples like pigments one has to record a diffuse reflection spectrum to determine the absorption spectrum in a qualitative way. In the attached ppts, you will find the details.

All the best for your research,

Thomas

There is no central database that keeps track of colorimetric agents, but here is a set of international standards:

Dear Dr. Perez,

Thanks for your answer.

Well... it can be done, but it is NOT easy. Your question is also somewhat ambiguous: are you trying to analyse a metal/ligand complex which is inherently liquid, or is it in solution in a solvent of some kind?

The easiest case is if it's soluble in water at such a concentration that the analyte element concentration is around 1 mg/litre (some elements need a lot more than this, a few require less). If you're working in an organic solvent, you'll need to be able to add extra air to cope with the combustion of the solvent (which means that when you switch between samples, you have to work FAST, because the flame will tend to go out: I've tried it - it's possible but NOT easy!)

Please can you be more specific about what precisely you're trying to do.

Do a Bradford assay as Adam mentioned, after clearing your extract by centrifugation or filtration. But for the love of god, do the A595/A465 ratio method. It has been around for over 30 years and people still do sole A595, probably right after waddling to the lab in Fred Flintstones car.

It got to be said, quantifying proteins is always a rule of thumb thing. The only true way of quantifying a protein is gravimetry, which is near impossible on an analytical scale. Depending on your protein composition (as Adam mentioned) you may end up with measured concentrations that may be off by a factor of 2 or seldomly even more. No matter whether you do A280, Bradford, BCA or any other measurement, proteins are hardly standardized.

Mikko Juhani Valkonen You are absolutely right to question things. In fact, Infrared Spectroscopy is an extrem fragmented field with different communities ranging from solid state physicists to biologists with very different levels of theory. Absorbance is, e.g., something that was rarely used 40 years ago. Integrating it means frequently that you have to remove baselines, which is a highly questionable practice from a theoretical point of view...

I cannot do much with a bad quality capture of a non-explained table. What I can see is that you have high RSD values (values above 5% are considered bad reproducibility), and considering that, the signals obtained for each dilution seem consistent to me. The dilutions and the decrese in signal are more or less proportional. Appart from the Non Diluted sample, which doesn't follow the trend. This may indicate that there is a systematical error in the dilution process.

Nevertheless, why are you using different dilutions for predicting a sample? You should simply choose the dilution whose signal lays in the middle of the linear range of your calibration. When you fix the lack of reproducibility issue, of course.

The poor recovery of calcium in your flame atomic absorption spectroscopy (F-AAS) analysis of alcoholic beverages after processing with a mixture of HNO3 65% and H2O2 30% could be attributed to several factors:

1-Interference from Matrix Effects: These matrix effects can lead to reduced recovery rates for calcium.

2-Chemical Reactions: Calcium can form complexes with other components present in the sample or react with the acids used during sample preparation, leading to incomplete recovery during the analysis process

3-Incomplete Sample Preparation

4-Instrumental Factors

To improve the recovery of calcium in your F-AAS analysis of alcoholic beverages, it is recommended to:

-Optimize the sample preparation method to ensure complete digestion and extraction of calcium.

-Consider using different acid mixtures or adjusting the concentrations to minimize interference and enhance calcium recovery.

-Verify the calibration and performance of the F-AAS instrument specifically for calcium analysis to ensure accurate results

What is the size range of your microplastic particles?

My first reaction would be to check if his oil/methanol emulsion may lead to scattering in the wavelength region he wants to use.

If so, this may well prevent any attempts at measuring anything by absorption.

Hello Noor Rehman

I managed to make a suspensions of ZnO and TiO2 nanoparticles, in ethanol. I tried concentration of 5 mg/mL, it gave me the behaviour I expected, but you must try less concentrated, like 1 mg/mL and 0.5 to check the result. I would say to you test what suits best for your nanoparticle, and find out if there is any solvent that harm your compound. For ZnO I could use water, but for TiO2 water was not suitable, so I used ethanol.

Best regards,

Ricardo Tadeu

Hey Henning,

I also stumbled upon that a few times. I guess the term hyperspectral does not imply any information on the technique itself.

In our publication on the topic, we therefore always used "hyperspectral imaging" to be clear about the technique.

That's why I'd answer your question with a), however, I'm happy to hear about different concepts.

Best,

Chris

Thank you so much, respected Martin Otto and João Carlos Martins da Costa for your valuable responses and suggestions.

Researchers in Prof. Richard Zare's laboratory have developed a fast, accurate mass spectrometry technique for distinguishing an individual's gender, age or ethnicity based on the chemical composition of sweat. This invention utilizes desorption electrospray mass spectroscopy imaging (DESI-MSI) to analyze both the fingerprint pattern and the composition of lipids and other metabolites from the sweat on the print. Next, a machine learning model (gradient boosting tree ensemble) further classifies the sample and predicts at a range of personal characteristics based on the DESI-MSI profile. Initial studies have correlated patterns of metabolites in sweat with age, gender and ethnicity. The model could be expanded to classify by medical condition or drug usage and it could be used to classify sweat samples collected alone without fingerprints. This invention could be a powerful tool to harness the enormous amount of chemical information provided by mass spectrometry for forensic or diagnostic testing.@Ruddhida Vidwans

The relationship, if you want to call it so, would be rather far-fetched. In TTS you normally investigate the tunneling of electrons, not protons. Now, in proton transfer processes the tunneling effect is a relevant subprocess, so if you model proton transfer reactions by theoretical methods, a tunneling correction to rate coefficients would be required or your calculated rates would be too slow. I haven't done such calculations myself since 2012, but even back then all the softwares I used had this option available.

The physics behind proton and electron tunneling is in both cases the quantum mechanical tunneling effect, but to my extent of knowledge that's as far as the relationship goes.

For a starter book you can read Weil & Bolton's book, http://xuv.scs.illinois.edu/516/handouts/weil%20bolton%20epr/weil&bolton.tableofcontents.pdf

"Electron Paramagnetic Resonance: Elementary Theory and Practical Applications". John A. Weil, James R. Bolton

ISBN: 9780471754961 DOI:10.1002/0470084987

Room-temperature optically detected magnetic resonance of single defects, Nature Communications volume 13, Article number: 618 (2022)

Dear Amirreza Malekzadeh Dirin, Tg is decreased becauae chains interdistance is increased due to the presence of surfactant molecules. This leads to a reduction of the Cohesive Energy Density (CED) responsible for chain mobility. Note that for most intermolecular forces, the energy of interaction is 1/r^6, r being the separation distance of intercting sites. The free volume decreases because it is filled by surfactant molecules which due to their size have both ease of mobility and packing beneath chains. Yes surfactants are used as plasticizers by acting as previously explained (chains separation). My Regards

Hi!

Thank you for your answers.

I will try to calculate.

Ok sir, I do not repeat , I do post such requests

Thanks so much, Ersin Sayar; the answers are helpful. I will try to adopt one of these techniques.

Infrared spectroscopy can sometimes be used for quantitative analysis, allowing for the determination of the concentration of a particular substance in a sample. This is achieved by measuring the intensity of absorption bands. Gas phase IR spectroscopy is versatile and can be applied to a wide range of samples, including gases, liquids, and solids.

The ability to analyze samples in the gas phase is particularly advantageous when dealing with volatile compounds. In gas phase IR spectroscopy, there is no interference from solvents or impurities that might be present in a sample. This contrasts with some liquid-phase techniques where the solvent absorption bands can become blended with the analyte.

Infrared spectroscopy is a non-destructive technique, meaning that it does not alter or damage the sample being analyzed. This is important when working with precious or limited quantities of a substance under review .

Gas phase IR spectroscopy is highly sensitive if the device range is pre-determined and can detect even small concentrations of molecules. This sensitivity makes it useful for analyzing trace amounts of substances in a sample and is highly selective. Different functional groups absorb infrared radiation at characteristic frequencies, allowing for the identification of specific chemical groups within a molecule. This selectivity is particularly useful in the identification of complex mixtures. The GPA is currently reviewing RAMAN laser techniques for gas analysis . ( GPA=Gas Processors Association) gas phase only !

Thank You Iswar Chandra Mondal

Analytica Chimica Acta 6.2 Impact Factor

spectroscopic camera is available in market you can use but it is not so useful

First, it's ultra violet and visible light spectroscopy, not ultra visible spectroscopy because you use both light ranges.

In these ranges you excite electron systems within the molecules. These may exhibit characteristic size effects (quantum dots, pi systems in organic dyes) or splittings (ligand field theory for inorganic complexes). Apart from that, for measurements of concentrations by the Lambert-Beer law, it's very precise.

If you are looking for something else, you have to be more specific.

XPS can be okay but it still has its limitations. It is a surface senstive technique and may provide slightly different composition than the bulk material.

Mössbauer spectroscopy definitely works. However, this techniques needs a gamma-radiation source and is not available in many labs.

"- Clay, solid sample (solid crystalline powders), can be swollen by water."

What do you mean? This is a statement not a question.

True Convergence means that an iterative process has reached a point where it is producing results that are stable and consistent. In other words, "true convergence" implies that the algorithm or method is effectively solving the problem it was designed for. On the other hand, "No Convergence" indicates that an iterative process or numerical method has not reached a stable or consistent solution after a certain number of iterations. In other words, the process may be oscillating or diverging, and it is not producing the desired result.

Madison Feehan Please do recommend my message if it was helpful

Selective Laser Melting (SLM) and Selective Laser Sintering (SLS) are advanced additive manufacturing technologies used to create three-dimensional objects by selectively melting or sintering layers of material powder. These technologies have applications not only on Earth but also in space. In-space manufacturing using SLM and SLS is gaining attention due to its potential to support long-duration space missions, colonization of other planets, and sustainability in space. Here are some of the technologies being enabled for SLM/SLS manufacturing in-space:

In-space SLM/SLS manufacturing has the potential to revolutionize space exploration by reducing the need to transport all equipment and spare parts from Earth. These technologies are still in development and will continue to evolve as space exploration efforts expand.

When analyzing the chemical makeup of various substances, including biological samples like biofluids, Fourier-transform infrared (FTIR) spectroscopy is a potent analytical method. It can be used to identify and research a number of diseases and medical conditions, including cholestasis, which is characterized by impeded liver bile flow. The liver condition cholestasis happens when the liver's natural flow of bile is obstructed or reduced. Bile is a fluid that the liver produces to help with digestion, particularly of fats in food. The rapidly developing techniques of Fourier Transform Infrared (FTIR) spectroscopy offer numerous advantages for the early diagnosis, grading, and monitoring of a wide range of liver diseases. Several studies have demonstrated that, in contrast to conventional histopathological investigations, infrared imaging holds great promise for understanding disease pathogenesis. Even minute amounts of chemical compounds can be identified thanks to FTIR's high accuracy and impressively detailed spectra. This is due to the fact that, unlike conventional Infrared technologies, the transform process makes the spectrum even more detailed than simply studying individual wavelengths.

It takes knowledge of infrared microspectroscopy, sample preparation, data collection, analysis, and interpretation to use infrared spectroscopy and microspectroscopy for the diagnosis, grading, and monitoring of liver diseases. With that being mentioned, the accuracy of biofluid FTIR spectroscopy in diagnosing patients with cholestasis depends on several factors including proper sample preparation for it is crucial to obtain accurate results. Other than that, although FTIR spectroscopy can identify changes in the biochemical makeup of biofluids, doing so necessitates a thorough knowledge of the pertinent biomarkers which makes the identification of specific biomarkers associated with cholestasis critical for accurate diagnosis. Lastly, depending on the degree and stage of cholestasis, the accuracy of FTIR spectroscopy may change. Compared to early-stage or mild cases, advanced cases may be more accurately detected.

There is still much to learn about the accuracy of using FTIR spectroscopy to diagnose cholestasis, and different studies have used different protocols, tools, and data analysis techniques. When assessing the suitability of FTIR spectroscopy for diagnosing cholestasis in a specific clinical context, it is crucial to take into account the state of the field and consult with medical experts. Before such methods are widely used for medical diagnosis, regulatory approvals, and clinical validation are also required.

References:

Biggers, A. (2018, November 13). Everything You Should Know About Cholestasis: Healthline. https://www.healthline.com/health/cholestasis

On A Whole New Wavelength: What Is FTIR And How Does It Work?. (n.d.). https://www.portableas.com/news/ftir-and-how-it-works/#:~:text=FTIR%20is%20highly%20accurate%20and,than%20simply%20studying%20individual%20wavelengths.

Spragg, R.A. (1999). IR Spectrometers: Fourier Transform Infrared Spectrometer. https://www.sciencedirect.com/topics/engineering/fourier-transform-infrared-spectrometer

No need to have the i-E curve. You can check the linearity by just varying the amplitude of your perturbation signal; you are in the linear domain if the impedance is independant of the amplitude.

Laser-Induced Breakdown Spectroscopy (LIBS) is a powerful analytical technique that can potentially be used to detect microplastics in water. Here's how it could be applied for this purpose:

1. Principle of LIBS:LIBS involves focusing a high-energy laser pulse onto a sample, which creates a microplasma or "spark" on the surface of the material. This microplasma emits light at characteristic wavelengths when the elements in the sample are vaporized and excited. By analyzing the emitted light, you can identify the elemental composition of the material.

2. Sample Preparation:For microplastics detection in water using LIBS, you would need to concentrate and collect the microplastic particles from the water sample. Filtration or centrifugation can be used to separate the microplastics from the water matrix.

3. Laser Interaction:Once the microplastic particles are collected, they can be placed on a sample holder. The high-energy laser pulse is focused on the surface of the microplastic, creating a microplasma. The vaporized material emits characteristic spectral lines that can be analyzed.

4. Spectral Analysis:The emitted light is collected and analyzed using a spectrometer. Each type of plastic can have specific elemental signatures due to the additives, pigments, or fillers used during manufacturing. These elemental signatures can be used to identify the type of plastic present in the sample.

5. Calibration and Identification:To detect microplastics, you would need to develop a calibration curve using known samples of different plastic types. By comparing the spectral lines of your unknown sample with the calibration curve, you can identify the type of plastic present.

6. Challenges and Considerations:Using LIBS for microplastics detection in water comes with challenges:

7. Data Analysis:After analyzing the emitted light, you'll need to interpret the spectra and use the calibration curve to determine the type of microplastic present in the sample.

LIBS has the potential to provide rapid, non-destructive, and element-specific analysis, which makes it an attractive option for microplastics detection. However, its successful application depends on optimizing the experimental setup, sample preparation, calibration, and data analysis to achieve accurate and reliable results. Given the complexity of the technique, collaboration with experts in LIBS and microplastics research would be beneficial. Alwielland Q. Bello

Calculated from what? Show us the graphical presentation.

Lahraseb Khan Thank you

Down below is the python code for the scheme above.

import math

def calculate_actual_reflectance(absolute_reflectance):

fraction = absolute_reflectance / 100.0

if fraction > 1:

actual_reflectance = 100

else:

actual_reflectance = absolute_reflectance * (1 - math.sqrt(1 - fraction))

return actual_reflectance

# Example usage:

absolute_reflectance = 250

actual_reflectance = calculate_actual_reflectance(absolute_reflectance)

print(actual_reflectance)

Another way to state the method is: Measure the rate of the reaction by finding the slope during the initial, linear part of the absorbance versus time plot. To do this, you must measure the absorbance at several times during the reaction.

Convert absorbance to concentration using the Beer-Lambert Law, as stated by Jürgen Weippert .

This means that no enough air or gas reachs the system. This normally caused by air compressor is not working or gas regulator is not will adjusted or selinoid valve problem.

May be simple problem: A = 1 - T - R

This equation is used in many papers.

example "The experimental results are shown in Fig. 1a,

b, respectively. From the R and T data, it is straightforward to obtain the absorption as A = 1 − R − T , which is of practical interest since it directly affects the optical efficiency."

You will need to implement a kind of lock-in detection to remove the background. One possibility would be to use the same chopping also at the spectrometer side. If you acquire data with and without this additional chopping, a weighted difference should remove the background and provide the desired data.

The abovementioned method will work only if the light intensities are stable over the measurement time. A real lock-in detection, that does not have this drawback, would require another detector than the one installed in the spectrometer USB4000.

What kind of interaction are you looking for? You probably will have some complex formation between nitrogen atoms of the DNA and the Nickel atoms which may replace Chloride as the ligand.

The Nickel UV-Vis is sensitive towards the coordination geometry, circular dichroism may add some chirality information to that. If that's what you're looking for, check out "Tanabe-Sugano diagrams" and associated literature.

If you want to see influences on bond strengths, infrared spectroscopy might be the tool of choice. There is also IR-CD spectroscopy, but I have never read into it.

If your Ni-DNA complex is paramagnetic, EPR spectroscopy would be an option, while if it's diamagnetic, you can do ⁶¹Ni NMR.

I think it possible to use only one prizm (grating double pass scheme): you can to decrease twice the dispertion

Dear Muhammad Shahbaz

Ferrites are materials that contain iron oxide and other metal oxides. The wide absorbance peaks observed in UV-vis spectroscopy of ferrites can be attributed to a number of factors:

Overall, the wide absorbance peaks observed in UV-vis spectroscopy of ferrites can be attributed to a combination of factors related to the crystal structure, electronic structure, particle size, and stoichiometry of the material.

A free version of EC-Lab can be downloaded at

ZSim and ZFit are powerful tools for learning impedance spectroscopy

Hi, Firas Khalid!

You can find a helpfull database at https://www.nist.gov/pml/atomic-spectra-database

At NIST's database, it is published the parameters which permits you to calculate Te for Boltzmann or Saha-Boltzmann (more than one species) for selected emitted lines in your spectra. Good luck!

Hi Luke Peters.. Thank you so much for the reply.. Good to hear that you belong to THz Imaging domain..

I think you will find that polyethylene is transparent (certainly looks that way to me). So visible will not work, but it may well absorb in the short wavelength UV (which cause degradation).

Mohammad Alzeyadi thank you very much for your detailed explanation

Are you talking about remote measurement or you can deploy your sensor in medium?

Dear Yongjin Kim ,

Although absorption and excitation spectra look (in general) quite similar they are fundamentally different terms, see for a pretty good explanation here: https://www.differencebetween.com/difference-between-excitation-and-vs-absorption/

See also https://www.edinst.com/blog/what-are-absorption-excitation-and-emission-spectra/

So, in ‘mechanistic terms’ different the absorption and excitation spectra show high resemblance in most cases, but there are examples where they differ (somewhat):

On, C., Tanyi, E. K., Harrison, E., & Noginov, M. A. (2017). Effect of molecular concentration on spectroscopic properties of poly (methyl methacrylate) thin films doped with rhodamine 6G dye. Optical Materials Express, 7(12), 4286-4295.

So, back to your question: you can get a pretty good idea about the excitation spectrum but strictly speaking you can only obtain an excitation spectrum by using fluorescence spectroscopy.

Best regards.

Well, I can't help much with the web site part, but if you want I could assemble a searchable database from your spectra, to be offered among the free databases here: https://www.effemm2.de/spectragryph/down_databases.html

Dear Dr. Abdullah Abdulkarim ,

as I already answered a similar question, I suggest you to have a look at the following, interesting and useful documents:

-Electrochemical Impedance Techniques Potentiostatic EIS by GAMRY Instruments

Available at: https://www.gamry.com/application-notes/EIS/potentiostatic-eis-tutorial/

-Basics of Electrochemical Impedance Spectroscopy by GAMRY Instruments

Available at: https://www.gamry.com/application-notes/EIS/basics-of-electrochemical-impedance-spectroscopy/

- Webinar Basics of Electrochemical Impedance Spectroscopy (EIS) by GAMRY Instruments

Available at: https://www.youtube.com/watch?v=GM0o1BbbXy8

- What is Electrochemical Impedance Spectroscopy (EIS)? By BioLogic

Available at: https://www.biologic.net/topics/what-is-eis/

- Electrochemical Impedance Spectroscopy (EIS) by Palmsens

Available at: https://www.palmsens.com/knowledgebase-article/electrochemical-impedance-spectroscopy-eis/

- Electrochemcal Impedance Spectroscopy (EIS) Basics by PINEresearch

Available at: https://pineresearch.com/shop/kb/theory/eis-theory/eis-basics/

- Electrochemical Impedance Spectroscopy by LibreTexts ENGINEERING

Available at: https://eng.libretexts.org/Bookshelves/Materials_Science/Supplemental_Modules_(Materials_Science)/Insulators/Electrochemical_Impedance_Spectroscopy

Enjoy reading and my best regards, Pierluigi Traverso.

The KnowItAll Academic edition is no longer available. The bet resources are to go back to the literature. These are the bet resources for interpretation. The Nakamoto book is particularly good for inorganics. You can find more information on the Coblentz website. www.coblentz.org

•Larkin, P.J. Infrared and Raman Spectroscopy. Principles and Spectral Interpretation, second edition; Elsevier: Cambridge MA, 2018

•Mayo, W.M., Miller, F.A., Hannah, R.W. Course Notes on the Interpretation of Infrared and Raman Spectra: Deducing Structures of Complex Molecules, first edition; John Wiley & Sons: New York, 2004

•Nakamoto, K. Infrared and Raman Spectra of Inorganic and Coordination Compounds, Part A: Theory and Applications in Inorganic Chemistry, Part B: Applications in Coordination, Organometallic, and Bioinorganic Chemistry, fifth edition;John Wiley & Sons: New York, 1997

•Socrates, G. Infrared Characteristic Group Frequencies, second edition;John Wiley & Sons: New York, 1994

•Lin-Vien, D.; Colthup, N.B.; Fateley, W.G.; Grasselli, J.G. Infrared and Raman Characteristic Frequencies of Organic Molecules, Academic Press: San Diego, 1991

•Colthup, N.B.; Daly, L.H.; Wiberley, S.E. Introduction to Infrared and Raman Spectroscopy, third edition; Academic Press: New York, 1990

•Bellamy, L.J.; The Infrared Spectra of Complex Molecules, Vol 1, third edition; Chapman and Hall: New York, 1975

The time domain quantification of metabolite signals was conducted using AMARES algorithm with custom prior knowledge.Metabolite concentrations were reported for tCr (creatine plus phosphocreatine), NAA (N-acetyl-aspartate), tCho (phosphocholine and glycerophosphocholine), Ins (myoinositol) and Glx (glutamate and glutamine). The AMARES prior knowledge model consisted of peaks for NAA, choline (Cho), creatine (Cr), glutamate + glutamine (Glx) and myoinositol (Ins). The amplitudes of NAA, Cho, Cr, Glx, and Ins peak were estimated by the algorithm. The relative phases of NAA, Cho, Cr, Glx, and Ins peak were fixed at 0. The linewidth of NAA was estimated by the algorithm, and the linewidths of the remaining peaks were set to be equal to that of NAA. The frequencies of NAA, Cho, Cr, Glx, and Ins peak were estimated by AMARES. All peak shapes were fixed at Lorentzian.

You could ask at the Indus facility (https://en.wikipedia.org/wiki/Indus_2), even if they don't have beamtime for you, they probably know people with smaller-scaled setups which would probably suffice for you.

TTA emission will have a quadratic dependence on incident light intensity, where other (1 photon) types of emission will have a linear dependence.

bulk and grain boundaries contributions may collapse . Your semi-circles atre distorted.

Thank you for your suggestions.

This sample is made of steel, which if cut each layer into a new surface for measurements up to 1 mm, it will certainly affect the microstructure due to heat and cutting force.

I thought of taking a side view of the sample surface. Then shoot a beam at the surface and shift the incident beam for each layer in micrometer steps. I don't know yet if these incident rays are smaller in diameter or equal to a few micrometers in size?

What makes you think so? The signature lines of a methylene groups are 1470, 2850 and 2925cm^-1. All these areas are covered here:

Moisture meter tests: This uses a specialized device called a moisture meter to determine the (%MC ) percentage moisture content of the material.

The pin meters use electrical resistance to measure the presence of water.

The less resistance there is to the electrical current, the more moisture there is in the plant matter.

Dear Dr. Stanislav Levun ,

I am, in general, in agreement with what was said by the colleagues who preceded me.

I would just like to point out that the best equivalent circuit is not said to be the one that thickens neglect with the experimental curve but the one that best represents the "real" system we are studying.

That is, to each component of the equivalent circuit we must be able to provide an explanation regarding its presence.

My best regards, Pierluigi Traverso.

As long as measurement are not in the UV (<350 nm), NMP (N-methyl-2-pyrrolidone) can be a useful solvent for optical absorption spectroscopy. We have used it with good results as a solvent for certain dyes and nanoparticles.

For emission studies, as for any solvent, always check the solvent emission background under the specific excitation and measurement conditions that you will use. Solvents may contain impurities depending on age, supplier, and history of the particular bottle used.

I recall that at a certain time, NMP was promoted as an alternative to its cousin DMF, but both are now considered harmful chemicals. Like DMF, NMP may contain traces of amines as impurities.

According to an article in Chemical&Engineering News, an alternative to NMP and DMF is being proposed: dihydrolevoglucosenone (commercial name "Cyrene"). I wonder if anyone has experience with this solvent for optical spectroscopy.

Good day! Here I found brief and complex explanation on reflectance and transmittance phenomenons:

The hamiltonian of such a system, usually, has the form H=H_S+H_{SR}+H_R, H_S is the hamiltonian of an isolated molecule, H_R is the hamiltonian of the radiation field, H_{SR}=\Sum_k (S^{+}+S)(a^{+}_k+a_k), here S operators refers to the system and a_k operators refers to the k-th mode of the radiation field. To see if there is enegry transition between eigenstates |x> and |y> of H_S, you should compute <y|H_{SR}|x>. If it is zero, there is no transition of such a type between |x> and |y>.

But you should take into account that there are more ways of an molecule to interract with the environment, for example dephasing H_{SR}=\Sum_k S^{+}S(a^{+}_k+a_k)

Yes, You should choose a line having no overlapping with other lines. In the case of overlapping results may differ.

I should think ICP would do the job, provided you can digest your particles. Would probably work using aqua regia or just HNO3 with some HCl added.

You can get relevant information here, to start with : https://www.inorganicventures.com/periodic-table

Dear Sumit, thank you for a nice question! I suspect that the difference between 2 notations, that the first one means the energy level or shell, so, for example, K shell can consist of 2 electrons, L 8 electrons ( L1 2, L2 2 and L3 4 anD overall it’s 8)and so on, the formula is 2n^2, so you see that when we talk about about shell one talks about several electrons, for the second notations you talk always about one electron on some level, this means that spin projection can be only plus minus 0.5, therefore only d 3/2 and 3/2 exist , for 0.5 one would need and electron with spin projection 3/2, which doesn’t exist, however for shell notations it’s fine, one just takes 3 electrons. For XPS it’s more convenient to talk about one electron notation because only one electron is involved and kicked out, however for Auger effect it’s always 2 of them, hope that my answer helps you.