Removing extra frontier parameters in QM/MM methods : a tentative with the Local Self-Consistent Field approach

Authors: Loos, P.F.¹; Fornili, A.²; Sironi, M.³; Assfeld, X.¹

Source: Computing Letters, Volume 3, Numbers 2-4, 2007 , pp. 473-486(14)

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Abstract:

We present a new quantum mechanics/molecular mechanics (QM/MM) scheme based on the Local-SCF method that avoids the extra-parametrization of the QM/MM frontier by taking into account the core electrons of the hybrid frontier atoms by means of self-consistent core orbitals (SCCO). This study follows and extends our previous investigation based on frozen core orbitals (FCO) [Chem. Phys. Lett. 427 236-240(2006)]. Test calculations on small organic compounds show that the most common atoms found in biochemical systems can be used as frontier atoms without adding any parameters, and that only relatively small geometric and energetic deviations compared to full-QM calculations are generated.

Keywords: QM/MM; LOCAL SELF-CONSISTENT FIELD; EXTREMELY LOCALIZED MOLECULAR ORBITALS; CORE ORBITALS; PARAMETRIZATION

Document Type: Research article

Affiliations: 1: Equipe de Chimie et Biochimie Théoriques, UMR 7565 CNRS-UHP, Institut Jean Barriol (FR CNRS 2843), Faculté des Sciences et Techniques, Nancy-Université, B.P. 239, 54506 Vandoeuvre-lès-Nancy Cedex, France 2: Biocrystallography Unit, DIBIT S. Raffaele Scientific Institute, Via Olgettina, 58 I-20132, Milano, Italy 3: Dipartimento di Chimica Fisica ed Elettrochimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy

Publication date: 2007-11-01