title: Calibration of Cholesky Auxiliary Basis Sets for Multiconfigurational Perturbation Theory Calculations of Excitation Energies.
abstract: The accuracy of auxiliary basis sets derived from Cholesky decomposition of two-electron integrals is assessed for excitation energies calculated at the state-average complete active space self-consistent field (CASSCF) and multiconfigurational second order perturbation theory (CASPT2) levels of theory using segmented as well as generally contracted atomic orbital basis sets. Based on 196 valence excitations in 26 organic molecules and 72 Rydberg excitations in 3 organic molecules, the results show that Cholesky auxiliary basis sets can be used without compromising the accuracy of the multiconfigurational methods. Specifically, with a decomposition threshold of 10(-4) au, the mean error due to the Cholesky auxiliary basis set is 0.001 eV, or smaller, decreasing with increasing atomic orbital basis set quality.
authors.affiliation: Department of Theoretical Chemistry, Chemical Center, University of Lund, P. O. Box 124 S-221 00 Lund, Sweden, Department of Physical Chemistry, Sciences II, University of Geneva, Quai E. Ansermet 30, 1211 Geneva 4, Switzerland, Instituto de Ciencia Molecular, Universitat de València, P. O. Box 22085, ES-46071 Valencia, Spain, and Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, P. O. Box 1033 Blindern, N-0315 Oslo, Norway.
authors.forename: Jonas
authors.initials: J
authors.lastname: Boström
authors.affiliation: Department of Theoretical Chemistry, Chemical Center, University of Lund, P. O. Box 124 S-221 00 Lund, Sweden, Department of Physical Chemistry, Sciences II, University of Geneva, Quai E. Ansermet 30, 1211 Geneva 4, Switzerland, Instituto de Ciencia Molecular, Universitat de València, P. O. Box 22085, ES-46071 Valencia, Spain, and Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, P. O. Box 1033 Blindern, N-0315 Oslo, Norway.
authors.forename: Mickaël G
authors.initials: MG
authors.lastname: Delcey
authors.affiliation: Department of Theoretical Chemistry, Chemical Center, University of Lund, P. O. Box 124 S-221 00 Lund, Sweden, Department of Physical Chemistry, Sciences II, University of Geneva, Quai E. Ansermet 30, 1211 Geneva 4, Switzerland, Instituto de Ciencia Molecular, Universitat de València, P. O. Box 22085, ES-46071 Valencia, Spain, and Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, P. O. Box 1033 Blindern, N-0315 Oslo, Norway.
authors.forename: Francesco
authors.initials: F
authors.lastname: Aquilante
authors.affiliation: Department of Theoretical Chemistry, Chemical Center, University of Lund, P. O. Box 124 S-221 00 Lund, Sweden, Department of Physical Chemistry, Sciences II, University of Geneva, Quai E. Ansermet 30, 1211 Geneva 4, Switzerland, Instituto de Ciencia Molecular, Universitat de València, P. O. Box 22085, ES-46071 Valencia, Spain, and Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, P. O. Box 1033 Blindern, N-0315 Oslo, Norway.
authors.forename: Luis
authors.initials: L
authors.lastname: Serrano-Andrés
authors.affiliation: Department of Theoretical Chemistry, Chemical Center, University of Lund, P. O. Box 124 S-221 00 Lund, Sweden, Department of Physical Chemistry, Sciences II, University of Geneva, Quai E. Ansermet 30, 1211 Geneva 4, Switzerland, Instituto de Ciencia Molecular, Universitat de València, P. O. Box 22085, ES-46071 Valencia, Spain, and Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, P. O. Box 1033 Blindern, N-0315 Oslo, Norway.
authors.forename: Thomas Bondo
authors.initials: TB
authors.lastname: Pedersen
authors.affiliation: Department of Theoretical Chemistry, Chemical Center, University of Lund, P. O. Box 124 S-221 00 Lund, Sweden, Department of Physical Chemistry, Sciences II, University of Geneva, Quai E. Ansermet 30, 1211 Geneva 4, Switzerland, Instituto de Ciencia Molecular, Universitat de València, P. O. Box 22085, ES-46071 Valencia, Spain, and Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, P. O. Box 1033 Blindern, N-0315 Oslo, Norway.
authors.forename: Roland
authors.initials: R
authors.lastname: Lindh