title: Integration of Ligand Field Molecular Mechanics in Tinker.
abstract: The ligand field molecular mechanics (LFMM) method for transition-metal complexes has been integrated in Tinker, an easily available and popular molecular modeling software package. The capability to calculate LFMM potentials has been provided by extending the functional forms of the Tinker package as well as by integrating routines for calculating the ligand field stabilization energy (LFSE), which is central to LFMM. The capabilities of the implementation are illustrated by both static calculations on the two spin states of [Fe(NH3)6](2+) and on [Cu(NH3)m](2+) (m = 4, 5, 6) and dynamic (LFMD) simulations of an FeN6-type spin-crossover compound. In addition to showing that results obtained with the Tinker-LFMM implementation are consistent with those of experiment and other computational methods and programs, we note that whereas LFMM is able to handle the conventional tetragonal Jahn-Teller distortion of the bond distances in [Cu(NH3)6](2+), the LFSE term is also necessary in order to obtain even qualitatively correct coordination geometries for the two lower-coordinate copper complexes.
authors.affiliation: †Department of Chemistry, University of Bergen, Allégaten 41, N-5007 Bergen, Norway.
authors.forename: Marco
authors.initials: M
authors.lastname: Foscato
authors.affiliation: ‡Inorganic Computational Chemistry Group, Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, Great Britain.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Deeth
authors.affiliation: †Department of Chemistry, University of Bergen, Allégaten 41, N-5007 Bergen, Norway.
authors.forename: Vidar R
authors.initials: VR
authors.lastname: Jensen
mesh_terms: D003300:Copper / Q000737:chemistry; D048088:Informatics / Q000379:methods*; D008024:Ligands; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D009584:Nitrogen / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D003300:Copper; D009584:Nitrogen