Ab initio calculations of free energy barriers for chemical reactions in solution

Journal Article · Thu Dec 07 04:00:00 EST 1995 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100049a009· OSTI ID:171448

Muller, R P; Warshel, A ^[1]

---

1. Univ. of Southern California, Los Angeles, CA (United States)

This paper develops and examines a hybrid ab initio quantum mechanical/molecular mechanics method for the calculation of activation free energies of chemical reactions in solution and in proteins. This method uses molecular mechanics force fields to simulate the solvent and ab initio technique that incorporates the potential from the solvent in its Hamiltonian to simulate the solute. The empirical valence bond (EVB) method is used as a reference potential for the ab initio free energy calculation. The utility of our method is illustrated by calculating the activation free energy for proton transfer from a water molecule to a hydroxide ion in both aqueous and nonpolar solutions. This paper also demonstrates that the EVB Hamiltonian can be refined easily by fitting the EVB parameters to the charges and energies resulting from ab initio gas phase calculations. 48 refs., 10 figs., 1 tab.

• Sponsoring Organization: USDOE
• DOE Contract Number: FG03-94ER61945
• OSTI ID: 171448
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 49 Vol. 99; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
99 GENERAL AND MISCELLANEOUS
ACTIVATION ENERGY
CALCULATION METHODS
CHEMICAL BONDS
CHEMICAL REACTIONS
FREE ENERGY
MOLECULAR ORBITAL METHOD
PROTEINS
QUANTUM MECHANICS
SOLUTIONS
SOLVENTS