A theoretical study of molecules trapped in an argon matrix: Vibrational energies, and transition moments for low-lying levels and IR bar spectra

2000 ◽  
Vol 12 (3) ◽  
pp. 435-448 ◽  
Author(s):  
A. Lakhlifi ◽  
H. Chabbi ◽  
P.R. Dahoo ◽  
J.L. Teffo
Keyword(s):  
Theoretical Study ◽  
Argon Matrix ◽  
Transition Moments ◽  
Vibrational Energies

A theoretical study of spectroscopic properties and transition moments of HBr

1987 ◽  
Vol 118 (3) ◽  
pp. 333-343 ◽  
Author(s):  
Douglas A. Chapman ◽  
K. Balasubramanian ◽  
S.H. Lin
Keyword(s):  
Theoretical Study ◽  
Spectroscopic Properties ◽  
Transition Moments

Experimental and Theoretical Study of the XYO (X, Y = Cl, Br) Light-Induced Interconversion in Argon Matrix

1998 ◽  
Vol 102 (43) ◽  
pp. 8222-8229 ◽  
Author(s):  
P. Chaquin ◽  
M. E. Alikhani ◽  
M. Bahou ◽  
L. Schriver-Mazzuoli ◽  
A. Schriver
Keyword(s):  
Theoretical Study ◽  
Argon Matrix

Infrared spectra of tautomers and rotamers of 9-methylguanine. An experimental and theoretical study

1991 ◽  
Vol 69 (11) ◽  
pp. 1705-1720 ◽  
Author(s):  
K. Szczepaniak ◽  
M. Szczesniak ◽  
W. Szajda ◽  
W. B. Person ◽  
J. Leszczynski
Keyword(s):  
Absorption Spectrum ◽  
Ab Initio ◽  
Infrared Spectra ◽  
Electronic Absorption ◽  
Ab Initio Calculation ◽  
Theoretical Study ◽  
Free Energies ◽  
Argon Matrix ◽  
Tautomeric Forms ◽  
Infrared Studies

Both amino-oxo and amino-hydroxy tautomeric forms of 9-methylguanine have been identified in approximately equal abundance in. infrared studies of these molecules isolated in the hydrophobic environment of an argon matrix at 12 K. The amino-hydroxy tautomer occurs in two different rotamers correlated with the rotation of the OH group. The ratio of concentrations of the two rotamers is sensitive to UV irradiation, and this ratio then relaxes to an equilibrium value after irradiation is stopped. This sensitivity allows us to separate the experimental spectra related to the oxo tautomer and to each of the rotamers of the hydroxy tautomer. The relative concentrations of the amino-oxo and amino-hydroxy tautomers ([a-o]/[a-h] = K(o-h) = 1.0 ± 0.3) and of the two rotamers (K(h1-h2) = 0.31 ± 0.10 in an argon matrix at 12 K and about 30 ± 15 in the vapor at 470 K) are estimated from the observed relative infrared absorbances. From these relative concentrations the differences between the free energies of the tautomers (ΔG470 (o-h) = 0 ± 0.5 kJ mol−1) and of the two rotamers (ΔG(h1-h2) = 0.12 ± 0.03 kJ mol−1 in the argon matrix at 12 K and ΔG470 between +2 and −13 kJ mol−1 in the vapor at 470 K) have been estimated. The electronic absorption spectrum of 9-methylguanine isolated in the argon matrix at 12 K and the effect of brief ultraviolet irradiation on it have also been studied. In an effort to interpret the experimental results, ab initio calculations of the infrared spectra have been made for 9-methylguanine at the 3-21G//3-21G level. Comparison with the experimental spectra is of some help with the assignment of the infrared spectra for the different tautomers. Key words: 9-methylguanine, tautomerism, infrared and ultraviolet spectra, matrix isolation, ab initio calculation.

scholarly journals A Theoretical Study on Vibrational Energies of Molecular Hydrogen and Its Isotopes Using a Semi-classical Approximation

2021 ◽  
Vol 21 (3) ◽  
pp. 725
Author(s):  
Redi Kristian Pingak ◽  
Albert Zicko Johannes ◽  
Fidelis Nitti ◽  
Meksianis Zadrak Ndii
Keyword(s):  
Molecular Hydrogen ◽  
Morse Potential ◽  
Theoretical Study ◽  
Potential Functions ◽  
Percentage Error ◽  
Quantization Rule ◽  
Classical Approximation ◽  
Vibrational Energies ◽  
Rosen Potential ◽  
Better Than

This study aims to apply a semi-classical approach using some analytically solvable potential functions to accurately compute the first ten pure vibrational energies of molecular hydrogen (H2) and its isotopes in their ground electronic states. This study also aims at comparing the accuracy of the potential functions within the framework of the semi-classical approximation. The performance of the approximation was investigated as a function of the molecular mass. In this approximation, the nuclei were assumed to move in a classical potential. The Bohr-Sommerfeld quantization rule was then applied to calculate the vibrational energies of the molecules numerically. The results indicated that the first vibrational transition frequencies (v1ß0) of all hydrogen isotopes were consistent with the experimental ones, with a minimum percentage error of 0.02% for ditritium (T2) molecule using the Modified-Rosen-Morse potential. It was also demonstrated that, in general, the Rosen-Morse and the Modified-Rosen-Morse potential functions were better in terms of calculating the vibrational energies of the molecules than Morse potential. Interestingly, the Morse potential was found to be better than the Manning-Rosen potential. Finally, the semi-classical approximation was found to perform better for heavier isotopes for all potentials applied in this study.

Theoretical Study of the Luminescent States and Electronic Spectra of UO2Cl2in an Argon Matrix

2011 ◽  
Vol 7 (10) ◽  
pp. 3293-3303 ◽  
Author(s):  
Jing Su ◽  
Yi-Lei Wang ◽  
Fan Wei ◽  
W.H.E. Schwarz ◽  
Jun Li
Keyword(s):  
Electronic Spectra ◽  
Theoretical Study ◽  
Argon Matrix

Theoretical study of electric dipole and transition moments of GeH, SnH, and PbH

1988 ◽  
Vol 88 (6) ◽  
pp. 3826-3833 ◽  
Author(s):  
Douglas A. Chapman ◽  
Junqing Li ◽  
K. Balasubramanian ◽  
S. H. Lin
Keyword(s):  
Electric Dipole ◽  
Theoretical Study ◽  
Transition Moments
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