𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Comparison of coupled-cluster and Brueckner coupled-cluster calculations of molecular properties

✍ Scribed by Rika Kobayashi; Henrik Koch; Poul Jørgensen; Timothy J. Lee

Publisher
Elsevier Science
Year
1993
Tongue
English
Weight
575 KB
Volume
211
Category
Article
ISSN
0009-2614

No coin nor oath required. For personal study only.

✦ Synopsis

The dipole moment, polarizabilities and hyperpolarizabilities of Ne, Be, BH, CH+, CO and NNO have been determined using the coupled-cluster and Brueckner coupled-cluster methods. The effect of orbital relaxation on these properties has been investigated implicitly, by carrying out singles and doubles coupled-cluster (CCSD) calculations with and without field relaxed SCF orbitals and explicitly through carrying out Brueckner doubles (BCCD) calculations. The effect of the connected triple excitations has been considered in the methods CCSD(T) and BCCD(T). The results show that allowing the SCF orbitals to relax in the presence of the field can make a significant difference to the CCSD properties. It has also been found that CCSD with field relaxed SCForbitals and BCCD give similar results.

📜 SIMILAR VOLUMES

A comparison of the efficiency and accur
A comparison of the efficiency and accuracy of the quadratic configuration interaction (QCISD), coupled cluster (CCSD), and Brueckner coupled cluster (BCCD) methods
✍ Claudia Hampel; Kirk A. Peterson; Hans-Joachim Werner 📂 Article 📅 1992 🏛 Elsevier Science 🌐 English ⚖ 1022 KB

The coupled-cluster method restricted to single and double excitations from a closed-shell reference function (CCSD) and the corresponding quadratic configuration interaction method (QCISD) are formulated in terms of quantities which can be computed directly from the two-electron integrals in A0 bas

A comparison of the efficiency and accur
A comparison of the efficiency and accuracy of the quadratic configuration interaction (QCISD), coupled cluster (CCSD), and Brueckner coupled cluster (BCCD) methods: Chem. Phys. Letters 190 (1992) 1
📂 Article 📅 1992 🏛 Elsevier Science 🌐 English ⚖ 32 KB

A comparison of the efficiency and accuracy of the quadratic configuration interaction (QCISD), coupled cluster (CCSD), and Brueckner coupled cluster (BCCD) methods, Chem. Phys. Lctters 190 (1992) 1.

Symmetry breaking in O+4: an application
Symmetry breaking in O+4: an application of the Brueckner coupled-cluster method
✍ Leslie A. Barnes; Roland Lindh 📂 Article 📅 1994 🏛 Elsevier Science 🌐 English ⚖ 746 KB

A recent calculation of the antisymmetric stretch frequency for the rectangular structure of quartet 0: using the QCISD(T) method gave a value of 37 10 cm-'. This anomalous frequency is shown to be a consequence of symmetry-breaking effects, which occur even though the QCISD (T) solution derived fro

Time-dependent coupled-cluster calculati
Time-dependent coupled-cluster calculations of polarizabilities and dispersion energy coefficients
✍ Richard J. Wheatley 📂 Article 📅 2007 🏛 John Wiley and Sons 🌐 English ⚖ 105 KB

## Abstract Time‐dependent coupled cluster theory, with unrestricted electron spins and full treatment of orbital rotation, is used to calculate polarizabilities at imaginary frequencies for Li, Ar, HCl, CO, N~2~, O~2~, and H~2~O, and to obtain dispersion energy coefficients for their pair interact

The optimization of molecular orbitals f
The optimization of molecular orbitals for coupled cluster wavefunctions
✍ Gustavo E. Scuseria; Henry F. Schaefer III 📂 Article 📅 1987 🏛 Elsevier Science 🌐 English ⚖ 434 KB

The purpose of this work is to make the coupled cluster (CC) energy stationary with respect to molecular-orbital (MO) variations in the reference configuration. To achieve this, we have used the Zvector, the solution of a set of perturbation-independent CPHF-like equations, to rotate the MOs. A new