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Structure of the ammonia dimer studied by density functional theory
Author(s) -
Zhu Tianhai,
Yang Weitao
Publication year - 1994
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/qua.560490507
Subject(s) - dimer , chemistry , maxima and minima , density functional theory , computational chemistry , hydrogen bond , ammonia , basis (linear algebra) , molecular physics , bond length , potential energy surface , atomic physics , thermodynamics , molecule , physics , geometry , mathematics , mathematical analysis , organic chemistry
Self‐consistent Kohn–Sham density functional calculations have been carried out to study the structure of the ammonia dimer. The local‐density approximation yields unusually large binding energy and short internitrogen distance compared with the experimental and more accurate theoretical data. The results from the Becke–Perdew gradient‐corrected functionals are generally in good agreement with those at the SCF MP 2 level when the geometry is fully optimized with various large basis sets. With our best estimation, the staggered quasi‐linear structure ( C s ) is 0.6 kcal/mol lower in energy than the symmetric cyclic one ( C 2 h ). The hydrogen‐bonded N—H bond in the staggered quasi‐linear structure is found to be 0.008 Å longer than the N—H bond in ammonia. In our calculations, we could not find the minima on the energy surface corresponding to the two asymmetric cyclic structures suggested by microwave spectra and coupled pair functional calculations. © 1994 John Wiley & Sons, Inc.