Basis Set Superposition Effects Research Articles

Exact perturbation treatment of the basis set superposition correction

It is shown that a complete removal of the basis set superposition effect on the interaction properties of a composite system can be understood in terms of constraints imposed on its wave function. This interpretation of the basis set superposition effect is used to build variation methods which account for the constraints imposed by the incompleteness of available solutions for the constituent subsystems. A perturbation analysis of the resulting constrained equations provides an exact method for the evaluation of the basis set superposition contribution to interaction properties. The corresponding perturbation correction is explicitly evaluated for the Hartree–Fock approximation and discussed at the level of different correlated methods.

Effect of basis-set superposition on the atomic charges and valencies in hydrogen- and lithium-bonded complexes

The effect of basis-set superposition on the MPA (Mulliken population analysis) and LPA (Löwdin population analysis) atomic charges and valencies has been studied for some H- and Li-bonded complexes using three standard basis sets and applying counterpoise (CP) and polarization counterpoise (PCP) correction methods. It has been observed that both MPA and LPA values change appreciably after CP correction. However, these changes are not always in conformity with our chemical intuition, and do not generally follow any definite trend with respect to the extension of basis sets. The PCP-corrected values do not differ significantly from the uncorrected ones.

Interaction energy decomposition and basis set superposition error analysis in hydrogen abstraction from the nitroxyl molecule by atomic hydrogen

In this paper we present an analysis, at the ab initio level, of the nature of the interaction energy for the hydrogen abstraction reaction H + HNO→H 2 + NO. We calculate the intramolecular (geometrical deformation) and intermolecular (electrostatic, polarization, exchange, charge transfer and mixing) components of the interaction energy and the basis set superposition effect (evaluated with the counterpoise, CP, and indirect counterpoise, ICP, techniques) in this reaction. It is observed that the application of the CP method in the HNO subsystem, described with minimal basis sets, produces an excess of basis set superposition error, which is corrected using the ICP method.

Van der Waals interaction potentials

The convergence of the many-body expansion for the interaction energy of helium is examined by performing matrix Hartree-Fock calculations on various geometrical arrangements of four helium atoms. Two-, three- and four-body interaction energies are determined. Basis set superposition effects are monitored by means of the site-site function counterpoise technique. The importance of four-body terms for certain geometries is demonstrated.

Ab Initio Calculation for the Interaction Energy of He–H

Abstract Using the help of an ab initio calculation with a configuration interaction (CI) treatment, the potential energies of a HeH system in the ground (X2Σ+) and the first three (A2Σ+, B2Π, C2Σ+) excited electronic states were calculated, making due correction for the basis set superposition effect.

Accurate evaluation of SCF and MP2 components of interaction energies. Complexes of HF, OH2, and NH3 with Li+

High-quality Gaussian basis sets of the well-tempered type, containing three sets of polarization functions on all atoms, are used to investigate the interaction of Li+ with HF, OH2, and NH3. These sets reproduce the SCF and MP2 energies of the various monomers very well and, moreover, accurately treat the multipole moments and polarizabilities of the monomers. When applied to the complexes, the sets are essentially free of primary and secondary basis set superposition error at the SCF level; MP2 extension effects are also completely negligible while basis set superposition effects are small but non-negligible. Analysis of the correlation corrections to the molecular properties, coupled with comparison of the interaction of the bases with a point charge, provides a straightforward explanation of correlation contributions to the interaction energy. Recommendations are provided to guide selection of basis sets for molecular interactions so as to avoid distortion of the various components.

MBPT studies of van der Waals molecules

The many-body perturbation theory is employed for the calculation of the interaction potential for the F- … He system in the framework of the supermolecule method. A particular attention is paid to the choice of the basis set functions for the two subsystems and the related basis set superposition effects. It has been found that the main features of the interaction potential are recovered in the SCF approximation. The SCF potential has its minimum at the distance R = 6·4 a 0 with the interaction energy of 53 cm-1. The complete fourth-order MBPT method gives the potential minimum position and depth equal to 6·5 a 0 and 64 cm-1, respectively. The basis set superposition effects estimated by using the counterpoise technique are negligibly small for the SCF interaction potential, while at the correlated level their magnitude is comparable to the value of the total correlation contribution to the interaction energy. The basis set superposition effect in calculations of the electron correlation contribution to ...

A many-body perturbation theory and coupled cluster study of the water dimer

The interaction energy of two water molecules is evaluated at several levels of theory in a better than double zeta plus polarization basis set. Our CCSD+T(CCSD) results should be quite close to the full CI result in this case. Results are compared with variation–perturbation results for the dispersion energy. Counterpoise-corrected correlated results are used to examine the importance of basis set superposition effects in this system.

MBPT studies of van der Waals molecules. III. The reliability of apparently accurate calculations for the magnesium dimer

The interaction potential for the magnesium dimer is calculated by using the diagrammatic many-body perturbation theory within the framework of the supermolecule approach. Different approximations for the perturbation treatment of the electron correlation effects are analysed with particular emphasis on the results of the complete fourth-order many-body perturbation theory. The influence of the composition of the basis set on the calculated interaction potentials and the basis set superposition effects are investigated. It is concluded that the interaction potentials for van der Waals systems calculated by the supermolecule technique might be highly uncertain because of the basis set superposition effects at the correlated level. The advantages and disadvantages of different methods for the calculation of the energy of weakly interacting systems are discussed in the light of their ability to cope with both the electron correlation problem and the basis set superposition effect.

Charge distribution analysis on Ar—H 2 system

The van der Waals Ar—H 2 system, using the RHF-SCF-LCAO-MO non-empirical method is studied. The change in the charge distribution (populations, multipolar moments and related properties) produced by the van der Waals interactions is analyzed and the influence of the basis set superposition effect is studied.

Van der Waals interaction potentials

Many-body contributions to van der Waals interaction potentials are discussed using the Hartree-Fock approximation as a zero-order model and diagrammatic many-body perturbation theory to describe electron correlation effects. A perturbation series is obtained for the effects of electron correlation on each of the terms in the expansion of the total interaction energy in its n-body components. Generalizations of the function counterpoise technique are used to allow for basis set superposition effects in calculations of many-body components of interaction energies. Prototype calculations are reported for the helium trimer.

Basis set superposition effects in electronic Populations Calculated on Hydrogen Bonded Systems

Basis set superposition effects, which may arise in Ab Initio calculations of electronic properties of the hydrogen bonded systems, are analized. The counterpoise technique of Boys and Bernardi in conjunction with the charge descomposition method of Morokuma is employed in order to examine the dependence of the components of the basis set superposition error. Prototype calculations for the HNOH 2O system are presented.

Van der Waals interaction potentials: Many-body basis set superposition effects

Basis set superposition effects in ab initio calculations of the many-body contribution to van der Waals interaction potentials are discussed, using generalizations of the function counterpoise correction of Boys and Bernardi. Prototype calculations using self-consistent-field theory are presented for the helium atom, the helium dimer and the helium trimer.

Improved SCF interaction energy decomposition scheme corrected for basis set superposition effect

AbstractA modified scheme for SCF interaction energy decomposition has been proposed where the nonphysical basis set superposition error (BSSE) has been corrected by means of the counterpoise method. A new procedure to separate the exchange and induction energy terms free of nonphysical BSSE has been tested in the case of the H2O dimer. The first order BSSE appears to be non‐negligible for strong hydrogen bonded complexes. In addition the scheme allows separation of the long‐controversial charge‐transfer contribution within the induction term, which has been considerably overestimated in previous studies.

Ab initio study of the pair potentials and electric dipole moments of the ArHe and NeHe diatoms

Large basis set Ab Initio calculations are reported for the variation of energy and electric dipole moment with internuclear separation for the diatoms ArHe and NeHe. Electron correlation effects are treated explicitly by the self consistent electron pairs method, and are found to be large. The effect of basis set superposition is examined, and found to be significant. Calculated potential well depths De and equilibrium internuclear separation Re compare with the em and Rm values found by fitting various experimental data. The electric dipole moment pe for the ArHe diatom at distances ≈ RIe is larger than that for the NeHe diatom, in accordance with the fact that the full collision induced absorption spectrum has been observed experimentally only for the latter. The variation of pe with R shows fine structure at R ≈ Re not previously reported.

Basis set superposition effects on properties of interacting systems. Dipole moments and polarizabilities

Basis set superposition effects which are not removed by the counterpoise correction are shown to modify the electric properties of interacting subsystems and influence indirectly the calculated interaction energies. The role of these higher-order basis set superposition effects is illustrated by the calculation of the water molecule dipole moment and polarizability in the basis set of the water dimer.

Basis set superposition effect on difference electrostatic molecular potential contour maps

Basis set superposition effect on difference electrostatic molecular potential contour maps