Journal ArticleDOI
The generalized active space concept in multiconfigurational self-consistent field methods.
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Test calculations on the Gd atom, Gd(2) molecule, and oxoMn(salen) complex show that GAS wave functions achieve the same accuracy as CAS wave functions on systems that would be prohibitive at the CAS level.Abstract:
A multiconfigurational self-consistent field method based on the concept of generalized active space (GAS) is presented. GAS wave functions are obtained by defining an arbitrary number of active spaces with arbitrary occupation constraints. By a suitable choice of the GAS spaces, numerous ineffective configurations present in a large complete active space (CAS) can be removed, while keeping the important ones in the CI space. As a consequence, the GAS self-consistent field approach retains the accuracy of the CAS self-consistent field (CASSCF) ansatz and, at the same time, can deal with larger active spaces, which would be unaffordable at the CASSCF level. Test calculations on the Gd atom, Gd2 molecule, and oxoMn(salen) complex are presented. They show that GAS wave functions achieve the same accuracy as CAS wave functions on systems that would be prohibitive at the CAS level.read more
Citations
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Journal ArticleDOI
Molcas 8: New capabilities for multiconfigurational quantum chemical calculations across the periodic table.
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TL;DR: The report includes the description of a computational machinery for nonlinear optical spectroscopy through an interface to the QM/MM package Cobramm.
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Journal ArticleDOI
Multiconfiguration Pair-Density Functional Theory.
Giovanni Li Manni,Rebecca K. Carlson,Sijie Luo,Dongxia Ma,Jeppe Olsen,Donald G. Truhlar,Laura Gagliardi +6 more
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Semistochastic Heat-Bath Configuration Interaction Method: Selected Configuration Interaction with Semistochastic Perturbation Theory
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Journal ArticleDOI
Multireference Approaches for Excited States of Molecules.
Hans Lischka,Hans Lischka,Hans Lischka,Dana Nachtigallová,Adelia J. A. Aquino,Adelia J. A. Aquino,Adelia J. A. Aquino,Péter G. Szalay,Felix Plasser,Felix Plasser,Francisco B. C. Machado,Mario Barbatti +11 more
TL;DR: The purpose of this review is to provide an overview of the most important facts about the different theoretical approaches available and to present by means of a collection of characteristic examples useful information, which can guide the reader in performing their own applications.
References
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Journal ArticleDOI
A complete active space SCF method (CASSCF) using a density matrix formulated super-CI approach
TL;DR: In this article, a density matrix formulation of the super-CI MCSCF method is presented, where the MC expansion is assumed to be complete in an active subset of the orbital space, and the corresponding CI problem is solved by a direct scheme using the unitary group approach.
Journal ArticleDOI
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Book
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