Finite-field calculations of molecular polarizabilities using field-induced polarization functions: second- and third-order perturbation correlation corrections to the coupled Hartree-Fock polarizability of H₂O

Abstract

Ordinary Rayleigh-Schr6dinger perturbation theory with Moller-Plesset (RSMP) partitioning is used to calculate second-and third-order correlation corrections to the CHF polarizability and dipole moment of the water molecule by a finite-field procedure. [2/1] Pad6 approximants are found to be useful in accelerating the convergence of the property perturbation expansions. Field-induced polarization functions suitable for polarizability calculations are determined. The average polarizability calculated, neglecting vibrational averaging, with Dunning's (9s5p/4s-4s2p/2s) contracted GTO basis set augmented by field-induced lslp2d/lp polarization functions is within 3 per cent of the experimental result. Correlation corrections to the dipole moment and polarizability of the water molecule calculated by the finite-field RSMP and single+double excitation CI(SDCI) methods for the same basis set are found to be in close agreement. The RSMP approach has the advantages of being size-consistent and of being capable of greater efficiency than the SCDI method. Comparative calculations carried out using EpsteinNesbet partitioning show that through third order RSEN correlation perturbation expansions for the dipole moment and polarizability are less rapidly convergent than RSMP expansions. However, reasonable accord with RSMP results can be achieved by using [2/1] Pad6 approximants to accelerate the convergence of RSEN energy perturbation expansions. The convergence of RSMP property correlation expansions based on the zeroth-order uncoupled-Hartree-Fock (UCHF) and coupled-Hartree-Fock (CHF) approximations are compared through third order. Whereas the CHF + RSMP expansions are for practical purposes fully converged, the UCHF+RSMP expansions are not adequately converged.

Transition Metal Hydrazide‐Based Hydrogen‐Storage Materials: the First Atoms‐In‐Molecules Analysis of the Kubas Interaction

“…Partial atomic charges were quantified using the Mulliken, Voronoi and Hirshfeld scales. These were calculated at the Gaussian optimised geometries using the Amsterdam Density Functional (ADF) program, [41][42][43] with the PBE functional, TZ2P basis sets [44][45][46][47][48] on all the atoms and the parameter controlling the integration grid set to 6.0. Mulliken charges were also calculated using the Gaussian code and Bader charges were taken from AIMALLPro.…”

Applicability of hybrid density functional theory methods to calculation of molecular hyperpolarizability

“…15 Another approach is to keep a medium-sized basis set and optimize the exponents of the basis functions to accurately reproduce specific molecular property of choice. An example of such a custom-designed basis sets was given by Chong et al 16 They used perturbation theory approach to derive field-induced polarization ͑FIP͒ functions for hydrogenic atom 17 and extrapolated the STO exponents to the atoms from H to Kr. The first-order functions ͑FIP1͒ were designed for calculations of ␣ and ␤, while second-order functions ͑FIP2͒ are necessary for calculations of the second hyperpolarizability ␥.…”

A density functional theory study of frequency-dependent polarizabilities and Van der Waals dispersion coefficients for polyatomic molecules

“…For the correct description of such sensitive properties as polarizabilities, it is mandatory to add diffuse functions to the basis. Our first extension of the 3Z2P basis, which we will denote by 3Z2P*, adds the diffuse s, p and d functions with exponents recommended by Zeiss et al 38,4 in the case of the H, F, N, O and C atoms. For the rare gas atoms we follow Colwell et al, 5 by adding diffuse s, p and d functions with exponents which were one third of the smallest exponents used in the standard 3Z2P basis.…”