Molecular mechanics (MM4) force field development for phosphine and its alkyl derivatives.
Based on the experimental structures and vibrational spectra of eight alkylphosphines, as well as ten ab initio calculated (MP2/6-31+g*) structures and five potential energy profiles, the MM4 force field has been extended to include this important functional group. The results are comparable to experimental values for phosphorus-containing compounds. The addition of various cross-terms significantly improved the MM4 calculated structures relative to its predecessor, MM3. The overall root mean square error in moments of inertia have been reduced from 1.65% in MM3 to 0.26% in MM4. MM4 was also successful in reducing the previously impressive root mean square error in vibrational frequencies from 35 cm(-1) to 31 cm(-1) for the eight compounds studied.
Todebush
Patricia Metthe
PM
The Computational Center for Molecular Structure and Design, Department of Chemistry, University of Georgia, Athens, Georgia, USA.
Liang
Guyan
G
Bowen
J Phillip
JP