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A wavefunction operator approach to the full-CI problem

✍ Scribed by A.V. Luzanov; A.L. Wulfov; V.O. Krouglov

Book ID
103031490
Publisher
Elsevier Science
Year
1992
Tongue
English
Weight
476 KB
Volume
197
Category
Article
ISSN
0009-2614

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✦ Synopsis

A new algorithm for the full-C1 problem in a determinantal basis is presented. Configurational coefftcients, being packed into the matrix of some wavefunction operator, are found from a suitable matrix equation. Combination of the variational CI problem in some restricted space with second-order perturbation theory allows us, for example, to study the CO2 molecule in a DZ + P basis set with an effective number of determinants of more than 10i5. Test calculations on H20, CHs, CHs, NHs and NHp show that in a DZ+ P basis a typical running time for Ending the correlation energy within 0.1% accuracy is just 3-10 times more than for the corresponding SCF procedure.

πŸ“œ SIMILAR VOLUMES

A full-CI investigation into the BSSE pr
A full-CI investigation into the BSSE problem
✍ I. Mayer; Á. VibΓ³k; P. Valiron πŸ“‚ Article πŸ“… 1994 πŸ› Elsevier Science 🌐 English βš– 508 KB

Full-CI calculations have been performed on the four-electron model systems He...He and H2...H2 in order to compare the a postedori Boys-Bernardi (counterpoise) and the a priori CHA ('chemical Hamiltonian approach') schemes for correcting BSSE ('basis set superposition error') at the electron correl