Calculating solution redox free energies with ab initio quantum mechanical/molecular mechanical minimum free energy path method
- Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States)
A quantum mechanical/molecular mechanical minimum free energy path (QM/MM-MFEP) method was developed to calculate the redox free energies of large systems in solution with greatly enhanced efficiency for conformation sampling. The QM/MM-MFEP method describes the thermodynamics of a system on the potential of mean force surface of the solute degrees of freedom. The molecular dynamics (MD) sampling is only carried out with the QM subsystem fixed. It thus avoids 'on-the-fly' QM calculations and thus overcomes the high computational cost in the direct QM/MM MD sampling. In the applications to two metal complexes in aqueous solution, the new QM/MM-MFEP method yielded redox free energies in good agreement with those calculated from the direct QM/MM MD method. Two larger biologically important redox molecules, lumichrome and riboflavin, were further investigated to demonstrate the efficiency of the method. The enhanced efficiency and uncompromised accuracy are especially significant for biochemical systems. The QM/MM-MFEP method thus provides an efficient approach to free energy simulation of complex electron transfer reactions.
- OSTI ID:
- 21559698
- Journal Information:
- Journal of Chemical Physics, Vol. 130, Issue 16; Other Information: DOI: 10.1063/1.3120605; (c) 2009 American Institute of Physics; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
60 APPLIED LIFE SCIENCES
ACCURACY
AQUEOUS SOLUTIONS
CHARGE EXCHANGE
COMPLEXES
DEGREES OF FREEDOM
EFFICIENCY
ELECTRON TRANSFER
FREE ENERGY
MOLECULAR DYNAMICS METHOD
ORGANIC COMPOUNDS
OXIDATION
QUANTUM MECHANICS
REACTION HEAT
REDUCTION
RIBOFLAVIN
SAMPLING
SIMULATION
SOLUTES
THERMODYNAMICS
CALCULATION METHODS
CHEMICAL REACTIONS
DISPERSIONS
ENERGY
ENTHALPY
HOMOGENEOUS MIXTURES
MECHANICS
MIXTURES
PHYSICAL PROPERTIES
SOLUTIONS
THERMODYNAMIC PROPERTIES
VITAMIN B GROUP
VITAMINS