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An ab initio study of the structure, dissociation energy, and heat of formation of Na 2 S
Author(s) -
Zhao Yongfang,
Gu Tingkun,
Pan Soufu,
Sun Jing
Publication year - 1997
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(1997)61:6<953::aid-qua8>3.0.co;2-v
Subject(s) - dissociation (chemistry) , standard enthalpy of formation , chemistry , basis set , ab initio , bond dissociation energy , electronic correlation , ground state , bent molecular geometry , atomic physics , thermodynamics , total energy , computational chemistry , molecule , physics , density functional theory , psychology , organic chemistry , displacement (psychology) , psychotherapist
The equilibrium geometries and fundamental frequencies of Na 2 S are calculated at HF, MP2(FC, FU), and MP3 with the 6–31G( d ) basis set and at HF and MP2(FC, FU) with the 6–31G( d ) basis set, respectively. The total energy at MP2(FU)/6–31G( d )‐optimized geometry is computed at MP4 with 6–311G( d, p ), 6–311 + G( d, p ), and 6–311G(2 df, p ), at QCISD(T)/6–311G( d, p ), and at MP2/6–311G(3 df , 2 p ) levels, respectively. The dissociation energy, the atomization energy, and the heat of formation for Na 2 S are evaluated using the G1 and G2 models. The calculated results indicated that Na 2 S in its ground state was a bent structure (C 2 v ). Electron correlation corrections on the bending angle are very significant. The equilibrium geometrical parameters are R e (Na‐S) = 2.45 Å and ∠Na‐S‐Na = 111.13° at the MP2(FU)/6–31G( d ) level. The theoretically estimated dissociation energy, total atomization energy, and heat of formation are 67.07, 117.55, and 0.35 kcal mol −1 , respectively, at 298.15 K. © 1997 John Wiley & Sons, Inc.