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Titolo:
Fragment mode analysis and its application to the vibrational normal modesof boron trichloride-ammonia and boron trichloride-pyridine complexes
Autore:
Matthaus, C; Wheeler, RA;
Indirizzi:
Univ Oklahoma, Dept Chem & Biochem, Norman, OK 73019 USA Univ Oklahoma Norman OK USA 73019 pt Chem & Biochem, Norman, OK 73019 USA
Titolo Testata:
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
fascicolo: 3, volume: 57, anno: 2001,
pagine: 521 - 534
SICI:
1386-1425(20010301)57:3<521:FMAAIA>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
FORCE-FIELD; THEORETICAL PREDICTION; PROJECTION ANALYSIS; SPECTRA; MOLECULES; FREQUENCIES; ACIDS; BASES;
Keywords:
normal mode; donor-acceptor complex; density functional; fragment mode analysis; basis transformation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
47
Recensione:
Indirizzi per estratti:
Indirizzo: Wheeler, RA Univ Oklahoma, Dept Chem & Biochem, Norman, OK 73019 USA Univ Oklahoma Norman OK USA 73019 ochem, Norman, OK 73019 USA
Citazione:
C. Matthaus e R.A. Wheeler, "Fragment mode analysis and its application to the vibrational normal modesof boron trichloride-ammonia and boron trichloride-pyridine complexes", SPECT ACT A, 57(3), 2001, pp. 521-534

Abstract

A method for expressing quantitatively the vibrational normal modes of a molecule in a basis set consisting of the normal vibrations (plus translations and rotations) of its constituent fragments is presented. The method is illustrated by describing the vibrational modes of BCl3-NH3 and BCl3-pyridine electron donor-acceptor complexes in terms of motions of BCl3 and eitherNH3 or pyridine. These complexes show examples of mixing between modes located on different fragments, mixing between modes of one fragment due to symmetry lowering, and the transformation of six fragment translations/rotations into vibrations of the complex. Although perturbation theory has been proposed to explain such examples of mode mixing, calculations imply that interactions between fragments of both complexes are too strong for perturbation theory to be generally applicable. In addition, the transformation of fragment rotations and/or translations into vibrations of the composite molecule will always occur and cannot be understood in detail by using perturbation theory. For the BCl3-pyridine complex, a band observed at 1107 cm(-1) is re-assigned as a combination of C-H in-plane bending and a ring-breathing mode of the pyridine fragment. (C) 2001 Elsevier Science B.V. All rights reserved.

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Documento generato il 09/07/20 alle ore 17:29:34