Recently, the convergence of the many-body sapt expansion for the interaction-induced dipole moment of He-H2 (24) and the polarizability of He2 (24, 32). has been checked by comparison with fci results in the same basis set. The numerical results for the helium dimer are summarized in Table 1 where we consider the anisotropy 7 and the trace a 7 = Aa — Aasx and a = (Act, + 2Aazz)/3, in which the z-axis is the molecular axis. An inspection of Table 1 shows that for all distances considered in Ref. (32) the many-body SAPT expansion reproduces the fci results to [Pg.124]

Some molecular properties which are of primary importance in calculations of intermolecular forces, like electric dipole moments, polarizabilities etc., are poorly reproduced by calculations with small basis sets. Evidently, these errors introduce errors into calculations of intermolecular forces, e.g. too large dipole moments yield too strong interactions. Table 3 shows convergence of the results on the (HF)2 complex when a near Hartree-Fock quality of the calculation is reached. [Pg.10]

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