Accurate ab initio predictions of the dissociation energy and heat of formation of first-row hydrides
1989; Elsevier BV; Volume: 163; Issue: 4-5 Linguagem: Inglês
10.1016/0009-2614(89)85155-3
ISSN1873-4448
AutoresJan M. L. Martin, J. P. François, R. Gijbels,
Tópico(s)Crystallography and molecular interactions
ResumoDissociation energies ΣDe of first-row hydrides can be computed ab initio to an accuracy of ±0.12 kcal/mol per bond using the CCD+ST(CCD)/6-311+G(2df, p)B model and CID/6-31G* geometries. Correlated geometries have a small, but non-negligible effect on computed dissociation energies when isogyric reactions are used. Some predicted values for experimentally poorly known ΣD0 values (ΔHf0 at 0 K) are (in kcal/mol): BeH 45.6±0.12 (82.5±1.3); BeH2 139.1±0.24 (40.6±1.4); BH 82.4±0.12 (105.1±3); BH2 159.4±0.24 (76.5±3.2); BH3 265.3±0.36 (22.3±3.3); NH 77.8±0.12 (86.3±0.22); NH2 170.3±0.24 (45.5±0.35) kcal/mol. The limiting factor as regards accuracy is the heat formation of the central atoms.
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