Spin-orbit matrix elements for internally contracted multireference configuration interaction wavefunctions

Berning, Andreas; Schweizer, Markus; Werner, Hans‐Joachim; Knowles, Peter J.; Palmieri, Paolo

doi:10.1080/00268970009483386

Cited by 948 publications

(586 citation statements)

References 53 publications

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“…Finally, the CP-corrected interaction potentials were point-by-point extrapolated to the basis set limit utilising the two-point (cubic) formula of Halkier et al [23,24] at each separation; these final potentials are denoted as RCCSD(T)/aV∞Z. To include the spin-orbit interaction, the CP-corrected interaction energies were used as the unperturbed eigenvalues of the Breit-Pauli spin-orbit matrix as implemented in MOLPRO to allow calculation of CP-corrected RCCSD(T) interaction energies inclusive of spin-orbit splitting at each separation, using the quadruple- and quintuple- basis sets as described; extrapolation of the resulting interaction energies was then performed [25].…”

Section: Computational Methodsology (A) Quantum Chemistrymentioning

confidence: 99%

Interactions of C ⁺ ( ² P _J ) with rare gas atoms: incipient chemical interactions, potentials and transport coefficients

Tuttle

Thorington

Viehland

et al. 2018

Phil. Trans. R. Soc. A.

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Accurate interatomic potentials were calculated for the interaction of a singly-charged carbon cation, C + , with a single rare gas atom, RG (RG = Ne-Xe). The RCCSD(T) method and basis sets of quadruple- and quintuple- quality were employed; each interaction energy is counterpoise corrected and extrapolated to the basis set limit. The lowest C + ( 2 P) electronic term of the carbon cation was considered, and the interatomic potentials calculated for the diatomic terms that arise from these: 2  and 2  + . Additionally, the interatomic potentials for the respective spin-orbit levels were calculated, and the effect on the spectroscopic parameters was examined. In doing this, anomalously large spin-orbit splittings for RG = Ar-Xe were found, and this was investigated using multireference configuration interaction (MRCI) calculations. The latter indicated a small amount of RG  C + electron transfer and this was able to rationalize the observations. This is taken as evidence of an incipient chemical interaction, which was also examined via contour plots, Birge-Sponer plots and various population analyses across the C + -RG series (RG = He-Xe), with the latter showing unexpected results. Trends in several spectroscopic parameters were examined as a function of the increasing atomic number of the RG atom. Finally, each set of RCCSD(T) potentials was employed including spin-orbit coupling to calculate transport coefficients for C + in RG, and the results compared to the limited available data.

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Section: Computational Methodsology (A) Quantum Chemistrymentioning

confidence: 99%

Interactions of C ⁺ ( ² P _J ) with rare gas atoms: incipient chemical interactions, potentials and transport coefficients

Tuttle

Thorington

Viehland

et al. 2018

Phil. Trans. R. Soc. A.

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“…19 Since the asymptotic SO splitting in M II itself is small ͑0.34 cm −1 ͒, 20 the corresponding SO states can be obtained perturbatively by diagonalizing Ĥ el + Ĥ SO in the ⌳ − ⌺ basis, where Ĥ el is the nonrelativistic Born-Oppenheimer molecular electronic Hamiltonian, Ĥ SO is the full microscopic Breit-Pauli SO operator, 21 and ⌳ and ⌺ are the projections of the electronic orbital angular momentum and spin on the molecular axis. In the present case, a 26ϫ 26 SO Hermitian matrix is constructed.…”

Section: A Relativistic Correctionsmentioning

confidence: 99%

Structure and spectroscopy of ground and excited states of LiYb

Zhang

Sadeghpour

Dalgarno

2010

The Journal of Chemical Physics

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Multireference configuration interaction and coupled cluster calculations have been carried out to determine the potential energy curves for the ground and low-lying excited states of the LiYb molecule. The scalar relativistic effects have been included by means of the Douglas-Kroll Hamiltonian and effective core potential and the spin-orbit couplings have been evaluated by the full microscopic Breit-Pauli operator. The LiYb permanent dipole moment, static dipole polarizability, and Franck-Condon factors have been determined. Perturbations of the vibrational spectrum due to nonadiabatic interactions are discussed.

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“…2 are shown curves calculated for the 2 ⌸ and 2 ⌺ ϩ states and the effect of including spin-orbit coupling employing the Breit-Pauli operator as implemented in MOLPRO. 39 In the latter calculations, CASSCF calculations are carried out with basis E ͑uncontracted͒, with the oxygen 1s and K 1s, 2s, and 2p electrons treated as core; the RCCSD͑T͒/basis B BSSE-corrected energies were used as the diagonal elements of the spin-orbit matrix.…”

Section: B Inclusion Of Spin-orbit Couplingmentioning

confidence: 99%

What is the ground electronic state of KO?

Lee

Soldán

Wright

2002

The Journal of Chemical Physics

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High-level, restricted coupled cluster with singles, doubles, and perturbative triples calculations are performed to determine the ground electronic state of KO. In the absence of spin-orbit coupling, we find that the ground state is a 2 ⌺ ϩ state, with a 2 ⌸ state lying just over 200 cm Ϫ1 higher in energy. We ascertain that basis set extension, higher-order correlation energy, mass-velocity, and Darwin relativistic terms do not change this ordering. We then calculate the low-lying ⍀ states when spin-orbit coupling is turned on. The 2 ⌺ 1/2 ϩ state undergoes an avoided crossing with the 2 ⌸ 1/2 state, and we therefore designate the ground state as X 1 2 . This state is essentially 2 ⌺ 1/2 ϩ at short R, but essentially 2 ⌸ 1/2 at long R; there is a corresponding A 1 2 state with the opposite behavior. These states have significantly different shapes and so spectroscopy from the adiabatic states. Finally, we calculate the dissociation energy D 0 , of KO as 66Ϯ1 kcal mol Ϫ1 and derive ⌬H f (KO, 0 K) as 13.6Ϯ1 kcal mol Ϫ1 .

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Spin-orbit matrix elements for internally contracted multireference configuration interaction wavefunctions

Cited by 948 publications

References 53 publications

Interactions of C ⁺ ( ² P _J ) with rare gas atoms: incipient chemical interactions, potentials and transport coefficients

Interactions of C ⁺ ( ² P _J ) with rare gas atoms: incipient chemical interactions, potentials and transport coefficients

Structure and spectroscopy of ground and excited states of LiYb

What is the ground electronic state of KO?

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Spin-orbit matrix elements for internally contracted multireference configuration interaction wavefunctions

Cited by 948 publications

References 53 publications

Interactions of C + ( 2 P J ) with rare gas atoms: incipient chemical interactions, potentials and transport coefficients

Interactions of C + ( 2 P J ) with rare gas atoms: incipient chemical interactions, potentials and transport coefficients

Structure and spectroscopy of ground and excited states of LiYb

What is the ground electronic state of KO?

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Product

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Interactions of C ⁺ ( ² P _J ) with rare gas atoms: incipient chemical interactions, potentials and transport coefficients

Interactions of C ⁺ ( ² P _J ) with rare gas atoms: incipient chemical interactions, potentials and transport coefficients