Fock-space coupled-cluster method: The (1,2) sector

Hughes, S. R.; Kaldor, Uzi

doi:10.1103/physreva.47.4705

Cited by 31 publications

(12 citation statements)

References 48 publications

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“…Where as the obvious advantage of defining H eff is to work within the model space and incorporate the effects of orthogonal space in an effective way. Restoring the operational space of H eff to P requires a set of constraint equations [49] and a previous work reported the implementation of particle-hole sectors [52] Fig. 3, from the potential intruder states 6p7p ( 3 P J ), 6s7s ( 3 S 1 ) and 6s7s ( 1 S 0 ).…”

Section: Incomplete Model Spacementioning

confidence: 99%

“…Where as the obvious advantage of defining H eff is to work within the model space and incorporate the effects of orthogonal space in an effective way. Restoring the operational space of H eff to P requires a set of constraint equations [49] and a previous work reported the implementation of particle-hole sectors [52] in relativistic CC calculations. However, all the good virtues of CMS, in the context of Fock-space CCT, are applicable when the model space is quasi-complete.…”

Section: Incomplete Model Spacementioning

confidence: 99%

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Fock-space relativistic coupled-cluster calculations of two-valence atoms

Mani

Angom

2011

Phys. Rev. A

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We have developed an all particle Fock-space relativistic coupled-cluster method for two-valence atomic systems. We then describe a scheme to employ the coupled-cluster wave function to calculate atomic properties. Based on these developments we calculate the excitation energies, magnetic hyperfine structure constants and electric dipole matrix elements of Sr, Ba and Yb. Further more, we calculate the electric quadrupole HFS constants and the electric dipole matrix elements of Sr + , Ba + and Yb + . For these we use the one-valence coupled-cluster wave functions obtained as an intermediate in the two-valence calculations. We also calculate the magnetic dipole hyperfine structure constants of Yb + .

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Section: Incomplete Model Spacementioning

confidence: 99%

“…Where as the obvious advantage of defining H eff is to work within the model space and incorporate the effects of orthogonal space in an effective way. Restoring the operational space of H eff to P requires a set of constraint equations [49] and a previous work reported the implementation of particle-hole sectors [52] in relativistic CC calculations. However, all the good virtues of CMS, in the context of Fock-space CCT, are applicable when the model space is quasi-complete.…”

Section: Incomplete Model Spacementioning

confidence: 99%

Fock-space relativistic coupled-cluster calculations of two-valence atoms

Mani

Angom

2011

Phys. Rev. A

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“…The FSMRCC theory [35][36][37][38][39][40][41][42][43][44][45][46][47][48] is originally based on the concept of effective Hamiltonian (EH). 12,13 This uses a common vacuum with respect to which holes and particles are defined.…”

Section: Effective Hamiltonian Formulation Of Fsmrcc Theorymentioning

confidence: 99%

A Lagrange multiplier approach for excited state properties through intermediate Hamiltonian formulation of Fock space multireference coupled-cluster theory

Gupta

Vaval

Pal

2013

The Journal of Chemical Physics

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In this paper, we present a formulation based on Lagrange multiplier approach for efficient evaluation of excited state energy derivatives in Fock space coupled cluster theory within the intermediate Hamiltonian framework. The formulation is applied to derive the explicit generic expressions up to second order energy derivatives for [1, 1] sector of Fock space with singles and doubles approximation. Its advantage, efficiency, and interconnection in comparison to the Lagrange multiplier approach in traditional formulation of Fock space, which is built on the concept of Bloch equation based effective Hamiltonian, has been discussed. Computational strategy for their implementation has also been discussed in some detail.

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“…The p-body equations for p 5 n are then obtained from (4) and iterated to convergence. Finally, the effective Hamiltonian matrix is constructed from (5) and diagonalized within the model space. The CCSD or SUB2 approximation results when (3) is truncated after &; inclusion of S3 yields the CCSDT or SUB3 scheme.…”

Section: ( 2 )mentioning

confidence: 99%

“…Preliminary applications to higher sectors of the Fock space have been reported by us. These include states with one electron ionized and two added to the closed shell [5] or more than two electrons added [6]. It was shown that the latter case required inclusion of triple excitations in the cc scheme to obtain good results.…”

Section: Introductionmentioning

confidence: 99%

The coupled‐cluster method in high sectors of the Fock space

Hughes

Kaldor

1995

Int J of Quantum Chemistry

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mThe coupled-cluster method is applied to high sectors of the Fock space (up to five electrons outside a closed shell). Ionization potentials and excitation energies are calculated for atomic N, 0, F, P, and S and their ions. The effect of virtual triple excitations is included, exactly or at several levels of appoximation. These terms are important for accurate results in the high sectors. 0 1995 John Wiley & Sons, Inc.

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Fock-space coupled-cluster method: The (1,2) sector

Cited by 31 publications

References 48 publications

Fock-space relativistic coupled-cluster calculations of two-valence atoms

Fock-space relativistic coupled-cluster calculations of two-valence atoms

A Lagrange multiplier approach for excited state properties through intermediate Hamiltonian formulation of Fock space multireference coupled-cluster theory

The coupled‐cluster method in high sectors of the Fock space

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