2018/02/28 by Maurus Schmid, Akshaya Kumar Das, Clark R. Landis +1 · 1 citation
Physics and Astronomy · Chemistry · #Advanced Chemical Physics Studies #Spectroscopy and Quantum Chemical Studies #Mass Spectrometry Techniques and Applications
paper · doi:10.1021/acs.jctc.7b01210
openalex publication_date 2018/02/28 · openalex created_date 2018/03/06 · openalex updated_date 2026/07/30
The implementation, validation, and application of the multi-state VALBOND method for transition-metal-containing and hypervalent molecules are presented. This approach is particularly suited for molecules with unusual shapes and systems that need to be described by a superposition of resonance structures, each of which satisfies the octet rule. The implementation is based on the original VALBOND force field and allows us to smoothly switch between resonance structures, each of which can be characterized by its own force field, including varying charge distributions and coupling terms between the states. The implementation conserves total energy for simulations in the gas phase and in solution and is applied to a number of topical systems. For the small hypervalent molecule ClF 3, the barrier for pseudorotation is found to be 4.3 kcal/mol, which compares favorably with the experimentally measured value of 4.8 kcal/mol. A transition-metal-containing complex, cisplatin, is characterized by six resonance states, for which the vibrational spectrum is found to be in good agreement with experiment. Finally, umbrella sampling simulations of the S N 2 reaction BrMe + Cl – → Br – + MeCl in solution yield a barrier height of 24.6 kcal/mol, in good agreement with experiment (24.7 kcal/mol).