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Intramolecular interaction effects and the structure of N 2 OS and N 2 O 2 : An Ab initio study
Author(s) -
Bock Charles,
Trachtman Mendel,
Schmiedekamp Ann,
George Philip,
Chin Tin S.
Publication year - 1983
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540040313
Subject(s) - conformational isomerism , basis set , ab initio , chemistry , anharmonicity , intramolecular force , computational chemistry , basis (linear algebra) , gaussian orbital , molecular geometry , force constant , ab initio quantum chemistry methods , crystallography , geometry , molecule , mathematics , density functional theory , physics , stereochemistry , quantum mechanics , organic chemistry
An ab initio study of ONNS with full geometry optimization has been carried out to corroborate the presence of an interaction between the terminal atoms in this type of structure, which, in ONNO, apparently stabilizes the cis conformer. Using the unscaled 4–31G basis set with a full set of d functions on the sulfur, there is a potential minimun at the trans but not the cis geometry. A gauche conformer with a torsional angle of 77.2° is the most stable. With N 2 O 2 this basis set gives potential minima at both the cis and trans geometries, but the trans conformer is slightly more stable, contrary to experiment and the results of (7,3) basis‐set calculations reported in the literature in which Gaussian lobe functions were employed. Using a (9,5) basis set there is no longer a potential minimum at the cis geometry, and a gauche structure is more stable than the cis conformer as in the case of N 2 OS with the less‐extended basis set. Force constants (harmonic and anharmonic), compliance constants, relaxed force constants, and interaction‐displacement coordinates for both molecules are compared for key structural elements.