Foster Mbaiwa

• Bsc, MPhil, AM, PhD
• Lecturer at Botswana International University of Science and Technology

The Africa Capacity-Building Initiative is a Royal Society programme funded by the former UK Department for International Development to develop collaborative research between scientists in sub-Saharan Africa and the UK. Initially, four institutions were involved in the Chem4Energy consortium: Cardiff University in the UK and three African partners...

Biodiesel has emerged as a possible replacement for fossil-based fuels, particularly in the transportation industry. Because of its high oxygen content, it has several limitations including high viscosity, pour point, and cloud point. Converting biodiesel to hydrocarbons is one method of improving the poor flow properties. In this study, Reactive F...

Biodiesel is one of the emerging renewable sources of energy to replace fossil-fuel-based resources. It is produced by a transesterification reaction in which a triglyceride reacts with methanol in the presence of a catalyst. The reaction is slow because of the low solubility of methanol in triglycerides, which results in low concentrations of meth...

γ-Butyrolactone (GBL) and γ-valerolactone (GVL) are two of the lactones with wide application in industry. The interactions of these two lactones with alcohols have been a subject of experimental research. This article reports the theoretical investigation of GBL/ethanol and GVL/ethanol mixtures throughout the entire composition range using molecul...

Biodiesel has emerged as a promising alternative fuel to replace dwindling fossil-based resources, particularly in view of its added environmental merit of reducing additional air pollution. Its specific attraction stems from the similarity of its physical properties to fossil fuel-derived diesel. Although the production of biodiesel is a relativel...

Molecular dynamics simulations of 2,2′-difurylmethane (DFM)/n-propanol and DFM/n-butanol binary liquid mixture have been performed using the optimized potentials for liquids simulations all-atom. The density and excess molar volume were computed with DFM mole fraction ranging from 0 to 1. There is excellent agreement between the calculated and expe...

Thermodynamic properties and structural aspects of 2,2′-difurylmethane (DFM) (1) and n-propanol (2) binary mixtures have been investigated using molecular dynamics simulation. Thermodynamic properties such as density, isothermal compressibility, enthalpy of vaporization, molar volume and excess molar volume are reported. In most cases the observed...

Aluminum and gallium co-doped ZnO (AGZO) thin films were grown by simple, flexible and cost-effective spray pyrolysis method on glass substrates at a temperature of 230 °C. Effects of equal co-doping with aluminum (Al) and gallium (Ga) on structural, optical and electrical properties were investigated by X-ray diffraction (XRD), UV-Vis-NIR spectrop...

The gas phase ion chemistry of coumarins using electron ionization (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI) in a time of flight and quadrupole mass spectrometer (qMS) coupled to a gas chromatograph is outlined. The observations in NCI mode were complimented with Ab initio calculations. This was because NCI gav...

The use of photoelectron angular distributions to provide structural details of cluster environments is investigated. Photoelectron spectra and angular distributions of I(-)·(H2O)2 and I(-)·(CH3CN)2 cluster anions are recorded over a range of photon energies. The anisotropy parameter (β) for electrons undergoes a sharp change (Δβmax) at photon ener...

Photoelectron imaging results are presented for I(-)[middle dot]X cluster anions (X = CO(2), C(4)H(5)N [pyrrole], (CH(3))(2)CO, CH(3)NO(2)). The available detachment channels are labeled according to the neutral iodine atom states produced (channel I ≡ (2)P(3/2) and channel II ≡ (2)P(1/2)). At photon energies in the vicinity of the channel II thres...

We present the results of a photoelectron imaging study of the I(-)·(CH(3)I)(2) cluster anion over excitation wavelengths 355-260 nm. The resulting spectra and photoelectron angular distributions (PADs) suggest extensive electron-molecule interaction following photoexcitation. Fragmentation channels are observed subsequent to excitation between 355...

Cl(-)·CH(3)I cluster anion photoelectron images are recorded over a range of detachment wavelengths in the immediate post threshold region. The photoelectron spectral features fall into two categories. A number of weak, photon energy dependent transitions are observed and attributed to atomic anion fragmentation products. Several more intense, high...

We present a comprehensive photoelectron imaging study of the O(2)(X  (3)Σ(g)(-),v(')=0-6)←O(2)(-)(X  (2)Π(g),v(")=0) and O(2)(a (1)Δ(g),v(')=0-4)←O(2)(-)(X  (2)Π(g),v(")=0) photodetachment bands at wavelengths between 900 and 455 nm, examining the effect of vibronic coupling on the photoelectron angular distribution (PAD). This work extends the v(...

The electron kinetic energy dependence of the photoelectron spectra and angular distributions of I(-)⋅CH(3)X (X=Cl,Br,I) cluster anions are measured via velocity mapped imaging at wavelengths between 350 and 270 nm. Processes analogous to those encountered in free CH(3)X-electron interactions are revealed. In particular, the presence and energies o...

Photoelectron angular distributions (PADs) recorded for the ${\mathrm{O}}_{2}$($X$ ${}^{3}{$\Sigma${}}_{g}^{$-${}}$) $$\leftarrow${}$ ${\mathrm{O}}_{2}^{$-${}}$($X$ ${}^{2}$${$\Pi${}}_{g}$) band show significant vibrational dependence. Experimental evidence of vibrational influence on the PAD has, to date, been sparse. Consequently, little attentio...

For atomic anions the photoelectron angular distribution (PAD) is a signature of the bound excess electron wavefunction. However, even for relatively simple molecular anions the relationship between the detachment orbital and the PAD is more complicated. We demonstrate this with a series of near threshold photoelectron images for superoxide detachm...

Photoelectron imaging measurements of I-\cdotCH3CN are presented from the lowest energy I(2P3/2)\cdotCH3CN channel threshold to 0.3 eV above the I(2P1/2)\cdotCH3CN threshold. Excitation of the cluster just below the latter threshold leads to competition between direct detachment and the production of a dipole-bound state [I(2P1/2)\cdotCH3CN]-. Subs...

I(-) x H(2)O and I(-) x CH(3)CN cluster anion photodetachment properties (photoelectron spectra and angular distributions) are recorded via velocity mapped photoelectron imaging for wavelengths between 270 and 340 nm, in small energy increments. These are compared with free I(-) detachment results and reveal the presence of a sharp change in the an...

Comparison of photodetachment images of I-CH3I with those of I- and I-CH3Cl over a range of wavelengths reveals generally similar spectral features but a strikingly different evolution of the photoelectron angular distributions. These measurements reveal the effect of intracluster electron scattering and in particular the influence of a vibrational...

Photoelectron imaging studies of I-·Pyn cluster anions, (Py = pyrrole, n = 1, 2) reveal two distinct photodetachment signatures. Transitions in which the binding energy is independent of the detachment wavelength are ascribed to direct detachment. Additional, low energy features showing a binding energy dependence on the detachment wavelength are t...

I⁻ and I⁻CH3I photodetachment over a range of wavelengths generally shows similar spectral features but strikingly different photoelectron angular distributions. The difference in angular distribution is due to intracluster electron scattering. Additionally, within narrow energy ranges, the cluster anion detachment yields new spectral transitions....

Photoelectron imaging probes both molecular electronic structure and electron molecule interactions. In the current work images were recorded for detachment from the I(-) x C(4)H(5)N (I(-) x pyrrole) cluster anion at wavelengths between 360 and 260 nm. The direct detachment spectra show strong similarities to those of I(-), although a strong solven...

I(-) and I(-)*CH(3)I velocity mapped photodetachment images are recorded over wavelengths between 270 and 370 nm. Spectral similarities, in conjunction with ab initio calculations show that the cluster anion comprises an atomic iodide anion moiety solvated by a relatively unperturbed CH(3)I molecule. Between 340-370 nm and at 280 nm, free I(-) is p...

Four chelate complexes, [Co(CNC6H3iPr2-2,6)3P(C6H4Me-p)2CH2CH2P(C6H4Me-p)2]BF4, [Co(CNC6H3iPr2-2,6)3PPh2CH=CHPPh2-cis]BF4, [Co(CNC6H3iPr2-2,6)3PPh2C6H4PPh2-o]BF4, and [Co(CNC6H3iPr2-2,6)3P(C6H4CF3-p)2CH2CH2P(C6H4CF3-p)2]BF4, have been synthesized by substitution reactions of [Co(CNC6H3iPr2-2,6)5]BF4 at elevated temperatures and/or prolonged reactio...

Five new complexes of the type [Co(CNC6H3iPr2-2,6)4PPh2-R′-PPh2]X, X=BF4, ClO4; R′=–(CH2)2– (1), –(CH2)3– (2), –CHCH-trans (3), –CC– (4) and –C6H4-p (5); and two new bimetallic complexes, [{Co(CNC6H3iPr2-2,6)4}2(μ-PPh2(CH2)3PPh2)](ClO4)2 (6) and [{Co(CNC6H3iPr2-2,6)4}2(μ-PPh2C6H4PPh2-p)](ClO4)2 (7), have been synthesized and characterized by variou...

In this dissertation results from experimental studies on the effect of the dipole moment on photodetachment from solvated iodide anion are presented. The major advantage of using solvated atomic iodide anions (I−·(Y)n (Y = solvent molecule, n=1 to 3)) to study this effect is that in the ground state, the excess electron is mainly localized on the...