The role of mid-bond basis set functions on the interaction energy and equilibrium structure of He and Hg vdW dimers; A revised view
Institute of Physical Chemistry and Chemical Physics, Slovak University of Technology, SK-812 37 Bratislava, Slovakia
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Abstract: The ground state ab initio CCSD(T) potential curves with various basis sets (aug-cc-pVXZ-PP (X = D, T, Q, 5, 6)) are presented for dimers of helium and mercury. In this context, the effect of parameter variations of the mid-bond functions with respect to the interaction energy and the equilibrium distance are discussed. Our results show that the use of the new optimized set of mid-bond functions in the aug-cc-pVQZ calculation will lower the interaction energy of helium to De = 33.21 mEh; closer to the experimental value of 34.68 mEh (Aziz, McCourt and Wong; Mol. Phys. 61 (1987) 1487). For the pseudohelium – mercury dimer, the usage of previously optimized mid-bond functions connected with the aug-cc-pVQZ-PP basis set calculation leads to the interaction energy De = 1713.15 mEh, which is in very good agreement with the experimental value of 1731.41 mEh of Ceccherini and Moraldi (Chem. Phys. Lett. 337 (2001) 386) and Koperski et al. (Chem. Phys. Lett. 219 (1994) 161). The quality of these results obtained using mid-bond functions with respect to the computational requirements is quite encouraging.
Keywords: bond-functions, Complete Basis Set, van der Waals, weak interactions
Full paper in Portable Document Format: acs_0091.pdf
Acta Chimica Slovaca, Vol. 4, No. 2, 2011, pp. 46—54