Showing papers by "Willis B. Person published in 1984"

Matrix isolation studies of nucleic acid constituents. 2. Quantitative ab initio prediction of the infrared spectrum of in-plane modes of uracil

Abstract: Calcul des derivees des moments dipolaires pour les atomes d'uracile en utilisant le programme GAUSSIAN 76 avec les fonctions de base 4-31 G. Etude des resultats

Infrared intensities of acetonitrile

Abstract: Mesure des intensites IR de CH 3 CN et CD 3 CN par une methode d'elargissement sous pression. Analyse des donnees obtenues

Quantitative prediction of infrared spectra of isolated molecular ions and radicals. 1. Carbonyl (CO+), carbon dioxide cation (CO2+), and carbon disulfide cation (CS2+)

Abstract: Calculs ab initio (4-31 G) des frequences et intensites des spectres IR de ces composes; comparaison aux calculs pour les molecules neutres correspondantes: les intensites des ions sont nettement inferieures a celles des especes neutres, ce qui est en accord avec les previsions basees sur les structures resonnantes de la theorie de la liaison de valence. Constantes de force

Vibrational spectra of uracils: Experimental infrared matrix studies and ab initio quantum‐mechanical calculations

Abstract: New experimental studies of the infrared spectra of uracil, 1-methyluracil, 3-methyluracil, and 1,3-dimethyluracil all isolated in Ar matrices at 10 K are compared with calculated spectra. The calculations for uracil are ab initio quantum-mechanical calculations of frequencies and intensities reported by us recently, and the CNDO calculations by Harsanyi and Csaszar. Both simulated calculated spectra agree quite well with the experimental infrared spectrum of matrix isolated uracil. Additional calculations have been made for the methyl-substituted uracils by transferring the ab initio calculated force constants and intensity parameters from uracil. A comparison of these calculated infrared spectra for 1-methyl-, 3-methyl-, and 1,3-dimethyluracil with the experimental spectra indicates the quality of the agreement. The potential-energy distributions are given for all the fundamental modes of the deuterated uracil derivatives and for the methyluracil molecules for the three fundamental vibrations of these molecules in the carbonyl region (1600–1800 cm−1). This comparison indicates the effect of methyl and deuterium substitution on the relative contributions of C2O, C4O, and C5C6 stretching motions to each fundamental mode. This result explains the puzzling anomalies in the intensity patterns observed experimentally in this region of the spectra of isolated deutero- and methyl-substituted uracil molecules.

Infrared intensities of acetonitrile

Abstract: Mesure des intensites IR de CH 3 CN et CD 3 CN par une methode d'elargissement sous pression. Analyse des donnees obtenues