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Theoretical studies of force fields and IR spectra of isocytosine
Author(s) -
Yan Guosen,
Xue Ying,
Xie Daiqian
Publication year - 1999
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1999)72:1<53::aid-qua5>3.0.co;2-w
Subject(s) - transferability , tautomer , force constant , ab initio , chemistry , force field (fiction) , basis set , computational chemistry , infrared , oxon , harmonic , spectral line , ab initio quantum chemistry methods , atomic physics , molecule , physics , density functional theory , stereochemistry , mathematics , quantum mechanics , organic chemistry , statistics , logit , neuroscience , biology
The optimized geometries, complete harmonic force fields, and infrared intensities of isocytosine tautomers, amino‐hydroxy and amino‐oxoN(1)H, were calculated at the ab initio Hartree–Fock level using the 6‐31G* basis set. The theoretical force fields were scaled by empirical scale factors, which were determined by fitting to the IR spectrum of the amino‐oxo form and were then transferred to the amino‐hydroxy form. The average deviations between experimental and computed frequencies are 7.6 cm −1 for amino‐oxo and 9.5 cm −1 for amino‐hydroxy, respectively. The assignments of the fundamental frequencies and the transferability of the force constant scale factors are also presented. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 72: 53–60, 1999