title: Multiconfigurational Self-Consistent Field Calculations of the Magnetically Induced Current Density Using Gauge-Including Atomic Orbitals.
abstract: Nondynamical electron correlation based on a genuine multiconfigurational theory is of considerable importance for a balanced ab initio calculation of aromatic and antiaromatic molecules either with open-shell character or quasi-degeneracy in the electronic states. Among the various aromaticity indices, the calculation of magnetically induced ring current densities (MICD) has emerged as a strong contender, providing both a qualitative and a quantitative description of the effect. We report here the first implementation of MICD at the multiconfigurational self-consistent field (MCSCF) level of theory together with example calculations. This extension makes the method applicable to systems that cannot be appropriately handled with earlier implementations based on a single-reference starting function. We present the formulation of the MCSCF MICD theory along with applications to a prototypical antiaromatic (cyclobutadiene) and an aromatic (benzyne) system, both systems that require a multiconfigurational description. We compare the MCSCF results to those obtained using Hartree-Fock and Kohn-Sham density functional theory and discuss the effects of static correlation on the aromaticity.
authors.affiliation: Raman Center for Atomic, Molecular and Optical Sciences, Indian Association for the Cultivation of Science , Kolkata 700 032, India.
authors.forename: Shubhrodeep
authors.initials: S
authors.lastname: Pathak
authors.affiliation: Laboratoire de Chimie et Physique Quantiques (UMR 5626), CNRS/Université de Toulouse 3 (Paul Sabatier) , 118 route de Narbonne, F-31062 Toulouse, France.
authors.forename: Radovan
authors.initials: R
authors.lastname: Bast
authors.affiliation: Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø , N-9037 Tromsø, Norway.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Ruud