caa a22 4500 605488088 CHVBK 20210128100453.0 cr unu---uuuuu 210128e20150801xx s 000 0 eng 10.1007/s00214-015-1703-x doi (NATIONALLICENCE)springer-10.1007/s00214-015-1703-x Novel orthogonalization and biorthogonalization algorithms [Elektronische Daten] Towards multistate multiconfiguration perturbation theory [Zsuzsanna Tóth, Péter Nagy, Péter Jeszenszki, Ágnes Szabados] Orthogonalization with the prerequisite of keeping several vectors fixed is examined. Explicit formulae are derived both for orthogonal and biorthogonal vector sets. Calculation of the inverse or square root of the entire overlap matrix is eliminated, allowing computational time reduction. In this special situation, it is found sufficient to evaluate the functions of matrices of the dimension matching the number of fixed vectors. The (bi)orthogonal sets find direct application in extending multiconfigurational perturbation theory to deal with multiple reference vectors. Springer-Verlag Berlin Heidelberg, 2015 Overlap nationallicence Orthogonalization nationallicence Biorthogonal sets nationallicence Multiconfiguration perturbation theory nationallicence Multistate theory nationallicence Tóth Zsuzsanna Laboratory of Theoretical Chemistry, Eötvös University, POB 32, 1518, Budapest, Hungary aut Nagy Péter MTA-BME Lendület Quantum Chemistry Research Group, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, POB 91, 1521, Budapest, Hungary aut Jeszenszki Péter Laboratory of Theoretical Chemistry, Eötvös University, POB 32, 1518, Budapest, Hungary aut Szabados Ágnes Laboratory of Theoretical Chemistry, Eötvös University, POB 32, 1518, Budapest, Hungary aut Theoretical Chemistry Accounts Springer Berlin Heidelberg 134/8(2015-08-01), 1-6 1432-881X 134:8<1 2015 134 214 https://doi.org/10.1007/s00214-015-1703-x text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00214-015-1703-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Tóth Zsuzsanna Laboratory of Theoretical Chemistry, Eötvös University, POB 32, 1518, Budapest, Hungary aut NATIONALLICENCE 700 1- Nagy Péter MTA-BME Lendület Quantum Chemistry Research Group, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, POB 91, 1521, Budapest, Hungary aut NATIONALLICENCE 700 1- Jeszenszki Péter Laboratory of Theoretical Chemistry, Eötvös University, POB 32, 1518, Budapest, Hungary aut NATIONALLICENCE 700 1- Szabados Ágnes Laboratory of Theoretical Chemistry, Eötvös University, POB 32, 1518, Budapest, Hungary aut NATIONALLICENCE 773 0- Theoretical Chemistry Accounts Springer Berlin Heidelberg 134/8(2015-08-01), 1-6 1432-881X 134:8<1 2015 134 214