Kin Long Kelvin Lee

Kin Long Kelvin Lee
Intel · Super Compute Group

B.Sc. (H1) PhD

About

118
Publications
5,618
Reads
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791
Citations
Introduction
My research involves the photodissociation dynamics of small organic molecules in the gas phase. Using a technique called Velocity-Mapped ion Imaging (VMI), I study how simple molecules such as acetone fragments after excitation with laser light. I can then try to model what I observe in the experiment by using a combination of high accuracy quantum chemistry and classical dynamics simulations.
Additional affiliations
August 2020 - present
Massachusetts Institute of Technology
Position
  • PostDoc Position
February 2017 - August 2020
Harvard-Smithsonian Center for Astrophysics
Position
  • PostDoc Position
December 2016 - February 2017
UNSW Sydney
Position
  • PostDoc Position
Education
March 2014 - August 2016
UNSW Sydney
Field of study
  • Physical Chemistry
March 2009 - November 2012
The University of Sydney
Field of study
  • Chemistry & Plant Biology

Publications

Publications (118)
Preprint
We present laboratory rotational spectroscopy of five isomers of cyanoindene (2-, 4-, 5-, 6-, and 7-cyanoindene) using a cavity Fourier-transform microwave spectrometer operating between 6-40 GHz. Based on these measurements, we report the detection of 2-cyanoindene (1H-indene-2-carbonitrile; 2-C$_9$H$_7$CN) in GOTHAM line survey observations of th...
Article
We have conducted an extensive search for nitrogen-, oxygen-, and sulfur-bearing heterocycles toward Taurus Molecular Cloud 1 (TMC-1) using the deep, broadband centimeter-wavelength spectral line survey of the region from the GOTHAM large project on the Green Bank Telescope. Despite their ubiquity in terrestrial chemistry, and the confirmed presenc...
Preprint
We have conducted an extensive search for nitrogen-, oxygen- and sulfur-bearing heterocycles toward Taurus Molecular Cloud 1 (TMC-1) using the deep, broadband centimeter-wavelength spectral line survey of the region from the GOTHAM large project on the Green Bank Telescope. Despite their ubiquity in terrestrial chemistry, and the confirmed presence...
Article
The unimolecular photodissociation dynamics of acetone spanning the entire S 1 ← S 0 absorption spectrum have been reinvestigated, with a focus on mechanisms that produce CO. At excitation wavelengths of λ > 305.8 nm, all photoproducts are formed on the S 0 state after internal conversion. A roaming mechanism forming C 2 H 6 + CO is active in the w...
Article
Full-text available
We report a systematic study of all known methyl carbon chains toward TMC-1 using the second data release of the GOTHAM survey, as well as a search for larger species. Using Markov Chain Monte Carlo simulations and spectral line stacking of over 30 rotational transitions, we report statistically significant emission from methylcyanotriacetylene (CH...
Article
We report a systematic study of all known methyl carbon chains toward TMC-1 using the second data release of the GOTHAM survey, as well as a search for larger species. Using Markov Chain Monte Carlo simulations and spectral line stacking of over 30 rotational transitions, we report statistically significant emission from methylcyanotriacetylene (CH...
Preprint
Full-text available
We report a systematic study of all known methyl carbon chains toward TMC-1 using the second data release of the GOTHAM survey, as well as a search for larger species. Using Markov-Chain Monte Carlo simulations and spectral line stacking of over 30 rotational transitions, we report statistically significant emission from methylcyanotriacetylene (CH...
Article
The rotational spectra of the singly substituted carbon-13 isotopic species of six sulphur-terminated carbon chains have been detected between 5 and 40 GHz using a supersonic discharge jet source in combination with a cavity Fourier transform microwave spectrometer. These molecules are HC3HS, a closed-shell isomer of H2C3S, and five radicals: HCCS,...
Article
Context. The chemical pathways linking the small organic molecules commonly observed in molecular clouds to the large, complex, polycyclic species long suspected of being carriers of the ubiquitous unidentified infrared emission bands remain unclear. Aims. To investigate whether the formation of mono- and polycyclic molecules observed in cold cores...
Preprint
Full-text available
The characterization of interstellar chemical inventories provides valuable insight into the chemical and physical processes in astrophysical sources. The discovery of new interstellar molecules becomes increasingly difficult as the number of viable species grows combinatorially, even when considering only the most thermodynamically stable. In this...
Article
Full-text available
Context. The recent interstellar detections of –CN containing aromatic species, namely benzonitrile, 1-cyanonaphthalene, and 2-cyanonaphthalene, bring renewed interest in related molecules that could participate in similar reaction networks. Aims. To enable new interstellar searches for benzonitrile derivatives, the pure rotational spectra of sever...
Article
jats:title>Abstract Polycyclic aromatic hydrocarbons (PAHs) have long been invoked in the study of interstellar and protostellar sources, but the unambiguous identification of any individual PAH has proven elusive until very recently. As a result, the formation mechanisms for this important class of molecules remain poorly constrained. Here we repo...
Preprint
The chemical pathways linking the small organic molecules commonly observed in molecular clouds to the large, complex, polycyclic species long-suspected to be carriers of the ubiquitous unidentified infrared emission bands remain unclear. To investigate whether the formation of mono- and poly-cyclic molecules observed in cold cores could form via t...
Article
The advent of chirped-pulse Fourier transform microwave spectroscopy has dramatically increased the acquisition rate of high-resolution data. However, this data is only useful when it can be translated into molecule-specific information, and ultimately chemical knowledge. To adapt to this high data rate regime, new data analysis tools, which do not...
Preprint
Polycyclic Aromatic Hydrocarbons (PAHs) have long been invoked in the study of interstellar and protostellar sources, but the unambiguous identification of any individual PAH has proven elusive until very recently. As a result, the formation mechanisms for this important class of molecules remain poorly constrained. Here we report the first interst...
Preprint
Full-text available
Evolved low- to intermediate-mass stars are known to shed their gaseous envelope into a large, dusty, molecule-rich circumstellar nebula which typically develops a high degree of structural complexity. Most of the large-scale, spatially correlated structures in the nebula are thought to originate from the interaction of the stellar wind with a comp...
Article
Evolved low- to intermediate-mass stars are known to shed their gaseous envelope into a large, dusty, molecule-rich circumstellar nebula which typically develops a high degree of structural complexity. Most of the large-scale, spatially correlated structures in the nebula are thought to originate from the interaction of the stellar wind with a comp...
Article
Identifying PAHs in space Midinfrared spectroscopy has shown that polycyclic aromatic hydrocarbons (PAHs) are abundant in many astronomical objects, but this technique cannot determine which specific PAH molecules are present. Radio astronomy could provide individual identifications if the molecule is sufficiently abundant and has a large dipole mo...
Preprint
Ubiquitous unidentified infrared emission bands are seen in many astronomical sources. Although these bands are widely, if not unanimously, attributed to the collective emission from polycyclic aromatic hydrocarbons, no single species from this class has been detected in space. We present the discovery of two -CN functionalized polycyclic aromatic...
Article
Pure rotational transitions of the deuterated NH3−H2 weakly bound complexes formed by NH3/ND3 and H2/D2, namely ND3−H2, NH3−D2 and ND3−D2, have been detected. Three different techniques, a millimeter-wave intracavity jet OROTRON spectrometer, molecular beam Fourier transform microwave (FTMW) cavity spectrometer and the broadband chirped pulse (CP)...
Article
jats:title>Abstract Using radio observations with the Green Bank Telescope, evidence has now been found for a second five-membered ring in the dense cloud Taurus Molecular Cloud-1 (TMC-1). Based on additional observations of an ongoing, large-scale, high-sensitivity spectral line survey (GOTHAM) at centimeter wavelengths toward this source, we have...
Preprint
Full-text available
Using radio observations with the Green Bank Telescope, evidence has now been found for a second five-membered ring in the dense cloud Taurus Molecular Cloud-1 (TMC-1). Based on additional observations of an ongoing, large-scale, high-sensitivity spectral line survey (GOTHAM) at centimeter wavelengths toward this source, we have used a combination...
Article
We report the discovery of two unsaturated organic species, trans-(E)-cyanovinylacetylene and vinylcyanoacetylene, using the second data release of the GOTHAM deep survey toward TMC-1 with the 100m Green Bank Telescope. For both detections, we performed velocity stacking and matched filter analyses using Markov Chain Monte Carlo simulations, and fo...
Article
Full-text available
Much like six-membered rings, five-membered rings are ubiquitous in organic chemistry, frequently serving as the building blocks for larger molecules, including many of biochemical importance. From a combination of laboratory rotational spectroscopy and a sensitive spectral line survey in the radio band toward the starless cloud core TMC-1, we repo...
Article
Full-text available
Benzonitrile (c-C6H5CN, where ‘c’ indicates a cyclic structure), a polar proxy for benzene (c-C6H6), has the potential to serve as a highly convenient radio probe for aromatic chemistry, provided that this ring can be found in other astronomical sources beyond the molecule-rich prestellar cloud TMC-1. Here we present radio astronomical evidence of...
Article
Full-text available
As the inventory of interstellar molecules continues to grow, the gulf between small species, whose individual rotational lines can be observed with radio telescopes, and large ones, such as polycyclic aromatic hydrocarbons best studied in bulk via infrared and optical observations, is slowly being bridged. Understanding the connection between thes...
Article
Full-text available
The evidence for benzonitrile (C6H5CN) in the starless cloud core TMC–1 makes high-resolution studies of other aromatic nitriles and their ring-chain derivatives especially timely. One such species is phenylpropiolonitrile (3-phenyl-2-propynenitrile, C6H5C3N), whose spectroscopic characterization is reported here for the first time. The low resolut...
Preprint
Full-text available
The evidence for benzonitrile (C$_6$H$_5$CN}) in the starless cloud core TMC-1 makes high-resolution studies of other aromatic nitriles and their ring-chain derivatives especially timely. One such species is phenylpropiolonitrile (3-phenyl-2-propynenitrile, C$_6$H$_5$C$_3$N), whose spectroscopic characterization is reported here for the first time....
Preprint
Full-text available
We report the discovery of two unsaturated organic species, trans-(E)-cyanovinylacetylene and vinylcyanoacetylene, using the second data release of the GOTHAM deep survey towards TMC-1 with the 100 m Green Bank Telescope. For both detections, we performed velocity stacking and matched filter analyses using Markov chain Monte Carlo simulations, and...
Preprint
Rotational transitions in vibrationally excited AlO and TiO -- two possible precursors of dust -- were observed in the 300 GHz range (1 mm wavelength) towards the oxygen rich AGB stars R Dor and IK Tau with ALMA, and vibrationally excited AlO was observed towards the red supergiant VY CMa with the SMA. The $J=11 \to 10$ transition of TiO in the $v=...
Preprint
The nebular circumstellar environments of cool evolved stars are known to harbour a rich morphological complexity of gaseous structures on different length scales. A large part of these density structures are thought to be brought about by the interaction of the stellar wind with a close companion. The S-type asymptotic giant branch star Pi1 Gruis,...
Article
The nebular circumstellar environments of cool evolved stars are known to harbour a rich morphological complexity of gaseous structures on different length scales. A large part of these density structures are thought to be brought about by the interaction of the stellar wind with a close companion. The S-type asymptotic giant branch (AGB) star π ¹...
Article
Full-text available
The nebular circumstellar environments of cool evolved stars are known to harbour a rich morphological complexity of gaseous structures on different length scales. A large part of these density structures are thought to be brought about by the interaction of the stellar wind with a close companion. The S-type asymptotic giant branch (AGB) star π1Gr...
Preprint
Full-text available
Much like six-membered rings, five-membered rings are ubiquitous in organic chemistry, frequently serving as the building blocks for larger molecules, including many of biochemical importance. From a combination of laboratory rotational spectroscopy and a sensitive spectral line survey in the radio band toward the starless cloud core TMC-1, we repo...
Preprint
Benzonitrile ($c$-C$_6$H$_5$CN), a polar proxy for benzene ($c$-C$_6$H$_6$}), has the potential to serve as a highly convenient radio probe for aromatic chemistry, provided this ring can be found in other astronomical sources beyond the molecule-rich prestellar cloud TMC-1 where it was first reported by McGuire et al. in 2018. Here we present radio...
Preprint
As the inventory of interstellar molecules continues to grow, the gulf between small species, whose individual rotational lines can be observed with radio telescopes, and large ones, such as polycyclic aromatic hydrocarbons (PAHs) best studied in bulk via infrared and optical observations, is slowly being bridged. Understanding the connection betwe...
Preprint
We report an astronomical detection of HC$_4$NC for the first time in the interstellar medium with the Green Bank Telescope toward the TMC-1 molecular cloud with a minimum significance of $10.5 \sigma$. The total column density and excitation temperature of HC$_4$NC are determined to be $3.29^{+8.60}_{-1.20}\times 10^{11}$ cm$^{-2}$ and $6.7^{+0.3}...
Preprint
Full-text available
We present an overview of the GOTHAM (GBT Observations of TMC-1: Hunting Aromatic Molecules) Large Program on the Green Bank Telescope. This and a related program were launched to explore the depth and breadth of aromatic chemistry in the interstellar medium at the earliest stages of star formation, following our earlier detection of benzonitrile (...
Article
Full-text available
The carbon chain ions HC3O + and HC3S +-longer variants of the famous "X-ogen" line carrier HCO +-have been observed for the first time using two cryogenic 22-pole ion trap apparatus (FELion, Coltrap) and two different light sources: the Free Electron Laser for Infrared eXperiments (FELIX), which was operated between 500 and 2500 cm −1 , and an opt...
Preprint
Full-text available
The carbon chain ions HC$_3$O$^+$ and HC$_3$S$^+$ - longer variants of the famous "X-ogen" line carrier HCO$^+$ - have been observed for the first time using two cryogenic 22-pole ion trap apparatus (FELion, Coltrap) and two different light sources: the Free Electron Laser for Infrared eXperiments (FELIX), which was operated between 500 and 2500 cm...
Article
Full-text available
Using chirped and cavity microwave spectroscopies, automated double resonance, new high-speed fitting and deep learning algorithms, and large databases of computed structures, the discharge products of benzene alone, or in combination with molecular oxygen or nitrogen, have been exhaustively characterized between 6.5 and 26 GHz. In total, more than...
Article
Some reactions produce extremely hot nascent-products which nevertheless can form sufficiently long-lived van der Waals (vdW) complexes—with atoms or molecules from a bath gas—as to be observed via microwave spectroscopy. Theoretical calculations of such unbound resonance-states can be much more challenging than ordinary bound-state calculations de...