Vincent Couling- PhD
- Lecturer at University of KwaZulu-Natal
Vincent Couling
- PhD
- Lecturer at University of KwaZulu-Natal
About
21
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Introduction
Current institution
Publications
Publications (21)
Measurements are reported of the depolarisation ratio for Rayleigh scattering by CO for gas pressures up to 5.1 MPa at the wavelength 632.8 nm. The first, second and third light-scattering virial coefficients are extracted, and compared with previous measurements in the literature at 514.5 nm and 488.0 nm. The first light-scattering virial coeffici...
The third-order nonlinear-optical susceptibility of dimethyl ether, (CH3)2O, has been measured in the gas phase over the wavelength range 488 nm < λ < 1064 nm using the technique of gas-phase electric-field-induced second-harmonic generation with periodic phase matching and with N2 as the reference gas. Measurements span a range of temperature, whi...
Measurements of the temperature dependence of the Buckingham effect (electric-field-gradient-induced birefringence, EFGIB) for gaseous carbon monoxide are presented. The measurements span the temperature range 301.2-473.9 K, which allows for separation of the temperature-independent hyperpolarizability contribution from the temperature-dependent qu...
Measurements of the temperature dependence of the Buckingham effect (electric-field-gradient-induced birefringence, EFGIB) for gaseous nitrous oxide are presented. Measurements span the temperature range 298.5-473.9 K, which allows for separation of the temperature-independent hyperpolarizability term from the temperature-dependent quadrupole term,...
The electric quadrupole moments of carbon dioxide and carbonyl sulphide have been measured via the technique of electric-field-gradient-induced birefringence (the Buckingham effect). Measurements for carbon dioxide span the temperature range 299.4 to 471.7 K, which allows for separation of the temperature-independent hyperpolarizability term from t...
An overview is given of theoretical and experimental work undertaken on the second Kerr effect virial coefficient B K, and a new molecular tensor theory of B K for molecules of nonlinear symmetry is presented. The theory is general, and includes molecules of higher symmetry as special cases. Calculated values for the polar axially symmetric molecul...
The second light-scattering virial coefficient, B ρ, of SO2 has been extracted from measurements of the depolarization ratio ρ at gas pressures up to 1 MPa. The value calculated using our recent molecular-tensor theory of B ρ for nonlinear molecules agrees with the experimental value to within 5%, providing further evidence that a comprehensive dip...
Current experimental work being undertaken on electro- and magneto-optical phenomena in the School of Physics, University of KwaZulu-Natal, is reviewed to introduce our research activity to the broader scientific community. I examine the Rayleigh-scattering, the Kerr electro-optic and the Cotton-Mouton magneto-optic experiments and show how molecul...
Measurements are reported of the depolarization ratio of (CH3)2O at vapour pressures up to 0.5 MPa, and the first and second light-scattering virial coefficients are extracted. The molecular-tensor theory of the second light-scattering virial coefficient Bρ for nonlinear molecules is extended to include for the first time those contributions in the...
Available information in relation to the anisotropic electric dipole polarizabilities of HCHO, CH3CHO, and CH3COCH3 is complemented by measurements of the vapor-phase Rayleigh depolarization ratios of HCHO and CH3CHO and the temperature dependence of the vapor-phase electrooptical Kerr effect of CH3COCH3 at 632.8 nm. In the cases of HCHO and CH3CHO...
Second Kerr effect virial coefficients B K of H2S have been calculated using our recent molecular tensor theory of B K for molecules of nonlinear symmetry. After optimization of the intermolecular potential interaction parameters and molecular quadrupole moment for H2S, the calculated B K values are seen to agree with the experimental values found...
The second light-scattering virial coefficient, Brho, of SO2 has been
extracted from measurements of the depolarization ratio rho at gas
pressures up to 1 MPa. The value calculated using our recent
molecular-tensor theory of Brho for nonlinear molecules agrees with the
experimental value to within 5% , providing further evidence that a
comprehensiv...
This paper presents a study of the use of ultraviolet resonance Raman (UVRR) spectroscopic methods as a means of elucidating aspects of drug-protein interactions. Some of the RR vibrational bands of the aromatic amino acids tyrosine and tryptophan are sensitive to the microenvironment, and the use of UV excitation radiation allows selective enhance...
An overview is given of theoretical and experimental work undertaken on
the second Kerr effect virial coefficient BK, and a new molecular tensor
theory of BK for molecules of nonlinear symmetry is presented. The
theory is general, and includes molecules of higher symmetry as special
cases. Calculated values for the polar axially symmetric molecules...
Ultraviolet resonance Raman spectroscopy was used to probe the change in the average environment of the seven tyrosine amino acids in barnase when the polypeptide chain folds from the denatured to the native state. The excitation radiation was continuous wave at a wavelength of 244 nm, and was generated from an intracavity-doubled argon ion laser,...
The second light-scattering virial coefficient B ρ of ethene has been extracted from measurements of the depolarization ratio ρ at gas pressures up to 3·2 MPa. The value calculated using our recent molecular tensor theory of B ρ for axially symmetric molecules, underestimates the experimental value by 40%. A complete molecular tensor theory of B ρ...
Measurements are reported of the depolarization ratios of CO2, N2, CH3CH3, CH3Cl and CO at gas pressures up to 5·2 MPa, and the first and second light-scattering virial coefficients are extracted. The apparatus and experimental procedures are described briefly. Experimental values of the second light-scattering virial coefficient are compared with...
Theory of the second light-scattering virial coefficient Bp is extended to include in the scattered intensity terms that have not previously been considered, namely dipole-dipole intensities of the fifth power in the molecular polarizability α as well as additional contributions arising from field gradient effects and induced quadrupole moments in...
