Toward a less costly but accurate calculation of the CCSD(T)/CBS noncovalent interaction energy

Abstract

The popular method of calculating the noncovalent interaction energies at the coupled-cluster single-, double-, and perturbative triple-excitations [CCSD(T)] theory level in the complete basis set (CBS) limit was to add a CCSD(T) correction term to the CBS second-order Møller-Plesset perturbation theory (MP2). The CCSD(T) correction term is the difference between the CCSD(T) and MP2 interaction energies evaluated in a medium basis set. However, the CCSD(T) calculations with the medium basis sets are still very expensive for systems with more than 30 atoms. Comparatively, the domain-based local pair natural orbital coupled-cluster method [DLPNO-CCSD(T)] can be applied to large systems with over 1,000 atoms. Considering both the computational accuracy and efficiency, in this work, we propose a new scheme to calculate the CCSD(T)/CBS interaction energies. In this scheme, the MP2/CBS term keeps intact and the CCSD(T) correction term is replaced by a DLPNO-CCSD (T) correction term which is the difference between the DLPNO-CCSD(T) and DLPNO-MP2 interaction energies evaluated in a medium basis set. The interaction energies of the noncovalent systems in the S22, HSG, HBC6, NBC10, and S66 databases were recalculated employing this new scheme. The consistent and tight settings of the truncation parameters for DLPNO-CCSD(T) and DLPNO-MP2 in this noncanonical CCSD(T)/CBS calculations lead to the maximum absolute deviation and root-mean-square deviation from the canonical CCSD(T)/CBS interaction energies of less than or equal to 0.28 kcal/mol and 0.09 kcal/mol, respectively. The high accuracy and low cost of this new computational scheme make it an excellent candidate for the study of large noncovalent systems.

Interactions between large molecules pose a puzzle for reference quantum mechanical methods

“…The L7 data set 28 and the C 60 @[6]CPPA buckyball-ring complex are arranged in terms of increasing interaction strength. Gray bars mark the range of interaction energies reported in the literature using alternative wavefunction-based methods (e.g., QCISD(T) 28 , and various local CCSD(T) approaches 49,51,52,[67][68][69][70] ). The yellow bars indicate the delta value (Δ min ) which is the minimum difference between best converged CCSD(T) and FN-DMC, given by the estimated and stochastic error bars (with 95% confidence interval), respectively.…”

“…C2C2PD has attracted the most attention to date in the CCSD(T) context as it represents a stepping stone between two widely studied systems: benzene dimer and graphene bilayer 9 . Already C2C2PD has posed a significant challenge to various local CCSD(T) methods due to its slowly-decaying long-range interactions 13,49,51,52,[67][68][69][70] . Considerable efforts have been devoted recently 13,49,51 to narrow down the local CCSD(T) interaction energy of C2C2PD to the range of about −19 to −21 kcal mol −1 .…”

Simultaneous exhibition of positive and negative cooperativity by purelyCH⋯OH‐bonded (1,3‐cyclohexanedione)n(n= 2–6) clusters: A density functional theoretical investigation

“…Further to check the reliability of energetic parameters calculated at ωB97X‐D/6‐311++G** level of theory, single point energies of CHD monomers and its dimers have been calculated at MP2/aug‐cc‐pVXZ (X = D,T) and DLPNO‐Y/aug‐cc‐pVTZ (Y = MP2,CCSD[T]) level of theories. Further extrapolation of these energetics have been performed up to CCSD(T)/CBS limit by using the two formula given by Chen et al [77] where, has been calculated by employing the approach proposed by Varandas and Pansini [78]. Here, the stabilization energy of dimers obtained at level was found to be very close to what was predicted by ωB97X‐D/6‐311++G** level.…”

“…Further extrapolation of these energetics have been performed up to CCSD(T)/CBS limit by using the two formula given by Chen et al [77]…”

A DLPNO‐CCSD(T) benchmarking study of intermolecular interactions of ionic liquids

“…replacing conventional CCSD(T) with the DLPNO analogue. 19 This was tested in neutral dimers of hydrogen bonded complexes, dispersion-dominated complexes and mixed complexes, in datasets S22, HSG, HBC6, NBC10, and S66for which both electrostatics and dispersion play equal roles. Mean average errors were found to be below 1 kJ mol À1 with respect to CCSD(T)/CBS.…”