Basis set and correlation effects in the calculation of accurate gas phase dimerization energies of two M-2(+) to give M-4(2+) (M = S, Se)
UNSPECIFIED. (2000) Basis set and correlation effects in the calculation of accurate gas phase dimerization energies of two M-2(+) to give M-4(2+) (M = S, Se). JOURNAL OF COMPUTATIONAL CHEMISTRY, 21 (3). pp. 218-226. ISSN 0192-8651Full text not available from this repository.
The dimerization energies of two M-2(+) to give M-4(2+) (M = S, Se) were calculated. They depend strongly on the size of the basis set and the correlation method used (ranging from 217 to 522 kJ/mol, M = S) and, therefore, a systematic study of basis set and correlation effects was performed [MP2, MP3, MP4(SDQ), CCSD, CCSD(T)]. The introduction of a second set of polarising d-functions caused a significant reduction of the dimerization energies, but neither of the above limits is reached by the MPn (n = 2, 3, 4) theory even with the largest basis sets [cc-pVQZ]. However, convergence was achieved by CCSD(T), compound methods or hybrid HF/DFT calculations employing flexible basis sets [e.g., CCSD(T)/cc-pV5Z, CBS-Q or B3PW91/6-311 + G(3df)] and revealed an average dimerization energy of 261 (199) kJ/mol for sulfur (selenium), Delta(r)H(298) (2S(2)(+) --> S-4(2+)) is 257 kJ/mol. In the selenium system the dependence on basis set and correlated method was less pronounced. (C) 2000 John Wiley & Sons, Inc.
|Item Type:||Journal Article|
|Subjects:||Q Science > QD Chemistry|
|Journal or Publication Title:||JOURNAL OF COMPUTATIONAL CHEMISTRY|
|Publisher:||JOHN WILEY & SONS INC|
|Official Date:||February 2000|
|Number of Pages:||9|
|Page Range:||pp. 218-226|
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