Computing the Position-Spread tensor in the CAS-SCF formalism

• Published in: Chemical physics letters Vol. 591; pp. 58 - 63
• Main Authors: El Khatib, Muammar, Leininger, Thierry, Bendazzoli, Gian Luigi, Evangelisti, Stefano
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20-01-2014; Elsevier
• Subjects: Chemical Sciences; or physical chemistry; Theoretical and
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2013.10.080

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•Implementation of the TPS tensor in the MOLPRO code for state-averaged CAS-SCF.•Application to Spiro mixed-valence system.•Presence of a spectacular maximum of the parallel TPS components for charge-transfer.
The Total Position Spread (TPS) tensor is a key quantity that describes the mobility of the electrons in a molecular system. The computation of the TPS tensor has been implemented for CAS-SCF wavefunctions in the MOLPRO code. This permits the calculation of this quantity for fairly large systems and wavefunctions having a strong multi-reference character. In order to illustrate the possibilities of the method, we applied the formalism to a mixed-valence Spiro-type system.