Applicability of the multi-reference double-excitation CI (MRD-CI) method to the calculation of electronic wavefunctions and comparison with related techniques

Buenker, Robert J.; Peyerimhoff, Sigrid D.; Butscher, Werner

doi:10.1080/00268977800100581

Cited by 1,019 publications

(211 citation statements)

References 30 publications

Supporting

Mentioning

209

Contrasting

Unclassified

Order By: Relevance

“…One such approach exists in the class of methods based on configuration interaction (CI), including CI itself [2] as well as the complete active space self-consistent field (CASSCF) method [3] and its CI-based (MRCI) [4] and perturbative (CASPT2) extensions [5]. CASSCFbased methods are among the most robust available and have the advantage of systematic convergence via expansions of the active space, but they suffer from the need * Electronic mail: eneuscamman@berkeley.edu for state-averaging and combinatorially growing costs.…”

Section: Introductionmentioning

confidence: 99%

Equation of Motion Theory for Excited States in Variational Monte Carlo and the Jastrow Antisymmetric Geminal Power in Hilbert Space

Zhao

Neuscamman

2016

J. Chem. Theory Comput.

View full text Add to dashboard Cite

An equation of motion formalism for excited states in variational Monte Carlo is derived and a pilot implementation for the Jastrow-modified antisymmetric geminal power is tested. In single excitations across a range of small molecules, this combination is shown to be intermediate in accuracy between configuration interaction singles and equation of motion coupled cluster with singles and doubles. For double excitations, energy errors are found to be similar to those for coupled cluster.

show abstract

Section: Introductionmentioning

confidence: 99%

Equation of Motion Theory for Excited States in Variational Monte Carlo and the Jastrow Antisymmetric Geminal Power in Hilbert Space

Zhao

Neuscamman

2016

J. Chem. Theory Comput.

View full text Add to dashboard Cite

show abstract

“…[41][42][43][44][45][46] In the first step of the calculations, Λ-S states are studied without considering any spin-orbit interaction. The actual computations have been carried out in the C 2V subgroup of C ∞V in which the GaBi molecule belongs.…”

Section: Details Of Computationsmentioning

confidence: 99%

Configuration Interaction Study of the Low-Lying Electronic States of GaBi

2002

View full text Add to dashboard Cite

Ab initio based multireference singles and doubles configuration interaction calculations, which include relativistic effective core potentials of the constituting atoms, have been carried out to study the low-lying electronic states of GaBi. Potential energy curves and spectroscopic constants of the electronic states within 46 000 cm -1 of energy have been reported. The ground-state dissociation energy of GaBi is calculated to be 1.24 eV as compared with the observed value of 1.60 ( 0.17 eV. Effects of the spin-orbit coupling on the spectroscopic properties of some low-lying states below 25 000 cm -1 have been studied. A large spin-orbit coupling produces a strong mixing among different Λ-S states and changes the characteristics of the potential energy curves. Several avoided crossings in the potential curves of Ω states of GaBi are also noted. The zero-field splitting of the ground state of GaBi is estimated to be 463 cm + component, which survives the predissociation, are reported to be highly probable. The radiative lifetime of A 3 Π 0 + is estimated, and the component is found to be shortlived. The oscillator strengths of 0 + -0 + and 0 + -1 transitions for the lowest few vibrational levels are reported. A comparison of the electronic spectrum of GaX(X ) P, As, Sb, Bi) molecules has been made.

show abstract

“…25 A number of additional integral programs [26][27][28] were required for treating the operators listed in Eqs. ͑2͒,͑3͒.…”

Section: Computationmentioning

confidence: 99%

Multireference configuration interaction calculations of electronic g-tensors for NO2, H2O+, and CO+

Lushington

Grein

1997

The Journal of Chemical Physics

View full text Add to dashboard Cite

Electronic g-tensors parametrize the Zeeman splitting observed in the EPR spectra of radicals. In this work, we report g-tensor calculations for NO 2 , H 2 O ϩ , and CO ϩ at the multireference CI level. Deviations of the tensor elements ͑g-shifts͒ from the free-electron value are computed via a perturbation expansion, complete to second order in relevant Breit-Pauli terms. The g-shifts we obtain for these molecules are as follows: NO 2 : ⌬g xx ϭ3571, ⌬g yy ϭϪ10296, ⌬g zz ϭϪ537; H 2 O ϩ : ⌬g xx ϭϪ249, ⌬g yy ϭ15733, ⌬g zz ϭ4105; CO ϩ : ⌬g Ќ ϭϪ2383, ⌬g ʈ ϭϪ181 ͓all values in parts per million ͑ppm͔͒. These results are in reasonable agreement with gas phase experimental data. Larger g-shifts are typically within 20% of experiment, whereas smaller g-shifts generally differ by no more than several hundred ppm. Basis set effects and gauge dependence are examined in the case of CO ϩ . For this molecule, a good valence description is vital for achieving accurate ⌬g-values and small gauge-dependence. Polarization functions are of some use in these calculations, but diffuse functions have little effect on the gauge dependence of a cationic radical such as CO ϩ . Vibrational effects are also examined for CO ϩ . The vibrationally averaged g Ќ -shift only differs from the equilibrium value by 83 ppm.

show abstract

Applicability of the multi-reference double-excitation CI (MRD-CI) method to the calculation of electronic wavefunctions and comparison with related techniques

Cited by 1,019 publications

References 30 publications

Equation of Motion Theory for Excited States in Variational Monte Carlo and the Jastrow Antisymmetric Geminal Power in Hilbert Space

Equation of Motion Theory for Excited States in Variational Monte Carlo and the Jastrow Antisymmetric Geminal Power in Hilbert Space

Configuration Interaction Study of the Low-Lying Electronic States of GaBi

Multireference configuration interaction calculations of electronic g-tensors for NO2, H2O+, and CO+

Contact Info

Product

Resources

About