Premium
Vibrational spectra and normal coordinate analysis of monohalogenated nitrobenzenes
Author(s) -
Muralidhar Rao P.,
Ramana Rao G.
Publication year - 1989
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250200809
Subject(s) - raman spectroscopy , force field (fiction) , chemistry , force constant , infrared , molecule , vibration , potential energy , molecular physics , valence (chemistry) , analytical chemistry (journal) , computational chemistry , atomic physics , physics , optics , quantum mechanics , organic chemistry , chromatography
The Raman and infrared spectra of o ‐, m ‐ and p ‐fluoronitrobenzenes, o ‐, m ‐ and p ‐chloronitrobenzenes, m ‐ and p ‐bromonitrobenzenes and o ‐, m ‐ and p ‐iodonitrobenzenes were measured. Far‐infrared and Raman polarization measurements were made wherever possible. A normal coordinate analysis was carried out for both the in‐plane and out‐of‐plane vibrations of these molecules using an 82‐parameter modified valence force field. An overlay least‐squares technique was employed to refine the force constants using 378 frequencies of the molecules to obtain a converged set of meaningful force constants. The reliability of the force constants so obtained was tested by making a zero‐order calculation for o ‐bromonitrobenzene. The potential energy distributions and eigenvectors calculated in the process were used to make unambiguous vibrational assignments of all the fundamentals.