Formation and physical characteristics of van der Waals molecules, cations, and anions: Estimates of complete basis set values
| Autor: | Libuše Šroubková, Rudolf Zahradník |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Basis (linear algebra)
Dimer Activated complex Thermodynamics Condensed Matter Physics Atomic and Molecular Physics and Optics chemistry.chemical_compound symbols.namesake chemistry Computational chemistry Ab initio quantum chemistry methods Potential energy surface symbols Molecule Physical and Theoretical Chemistry van der Waals force Basis set |
| Zdroj: | International Journal of Quantum Chemistry. 104:52-63 |
| ISSN: | 1097-461X 0020-7608 |
| DOI: | 10.1002/qua.20579 |
| Popis: | Complete basis set (CBS) values are sought either for highly accurate molecular characteristics of small species (e.g., pairs of rare gas atoms or the HF dimer) or for medium-size molecules or ions (e.g., bases of nucleic acids, the benzene dimer). In the latter case, only the Moller–Plesset type 2 (MP2) procedure with DZ and TZ basis sets is feasible. In the present work, both aspects are relevant. Altogether 23 species and 7 reactions are treated, including van der Waals (vdW) molecules ((H2)2, rare gas dimers), cations (H … Rg, Rg = He, Ne, Ar, Kr), and anions associated with the CH potential energy surface (CH4 … H−, CH … H2, and the CH (D3h) Eyring activated complex). Use has been made of various extrapolation formulas. An exponential-type formula is also reliable in instances when only small basis set data are available. By means of a formula used in our previous work (FX = F∞ + a n−1, where FX is a physical characteristics obtained with a cc-pVXZ basis set and X is the cardinal number, F∞ a CBS value searched for, and n the total number of atomic functions in the basis set), it is possible to show that CBS ΔE values of association processes (e.g., A + B ⇋ A − B, where A and B are held together by a bond of variable strength) are essentially the same, regardless of whether simple or augmented basis sets are used when considering or neglecting corrections for the basis set superposition error (BSSE). © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 |
| Databáze: | OpenAIRE |
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