The Challenge of ab Initio Calculations in Small Neon Clusters

Abstract

Weakly bound neon dimer, trimer and tetramers are studied at HF and CCSD(T) levels using Dunning, ANO and SIGMA‐s basis sets. Their ground‐state binding energies are studied along with some structural properties. SIGMA‐s basis sets have been developed explicitly for this issue but in a manner that can be readily applied to other atoms for the study of larger weakly bound systems. The difficulties for attaining accurate results on these systems are assessed by the computation of total, atomization and correlation energies, as well as equilibrium distances, with several basis sets of increasing size, ranging from non‐augmented to double‐augmented versions. Extrapolations are proposed to predict stabilization energies and the results are compared with previously published data.

Impact of Combination Rules, Level of Theory, and Potential Function on the Modeling of Gas- and Condensed-Phase Properties of Noble Gases

“…In contrast to what is expected based on theory, the C8 term in the TT potential (eq ) converges to zero except for dimers including Neon (e.g., Tables S46 and S36). It is well-known that very high levels of theory are needed to accurately predict dispersion coefficients or indeed to even get the position of the energy minimum of the neon dimer correct . This is why other studies , rely on dispersion coefficients from time-dependent many-body perturbation theory methods …”

“…It is well-known that very high levels of theory are needed to accurately predict dispersion coefficients 93 or indeed to even get the position of the energy minimum of the neon dimer correct. 94 This is why other studies 20 , 68 rely on dispersion coefficients from time-dependent many-body perturbation theory methods. 95 …”