Nuclear quadrupole coupling constant of Ne-21 in the neon dimer and its influence on the T-1 NMR relaxation time in fluid neon

The coupled cluster singles and doubles (CCSD) and CCSD combined with a per turbative correction for triple excitations (CCSD(T)) wave-function models are applied to study the effect of interatomic interactions in the Ne dimer on the electric field gradient (EFG) at the Ne atoms. Large one-electron b asis sets are used to describe simultaneously the correlation corrections a nd the effect of the interatomic interaction on the EFG. The resulting pote ntial and EFG curves are used in molecular dynamics simulations to determin e the T-1 NMR relaxation time in supercritical and liquid Ne-21. The role o f various approximations and the accuracy of the obtained results can now b e systematically analyzed, and the calculations therefore make a reliable p rediction of the relaxation times possible. (C) 2000 Elsevier Science B.V. All rights reserved.