Charge equilibration for molecular dynamics simulations: Difference between revisions
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'''Charge equilibration''' (QEq) for [[molecular dynamics]] simulations <ref>[http://dx.doi.org/10.1021/ja00290a017 Wilfried J. Mortier, Karin Van Genechten, Johann Gasteiger "Electronegativity equalization: application and parametrization", Journal of the American Chemical Society '''107''' pp. 829-835 (1985)]</ref> <ref>[http://dx.doi.org/10.1021/j100161a070 Anthony K. Rappe and William A. Goddard III "Charge equilibration for molecular dynamics simulations", Journal of Physical Chemistry '''95''' pp. 3358-3363 (1991)]</ref> is a technique for calculating the distribution of charges | '''Charge equilibration''' (QEq) for [[molecular dynamics]] simulations <ref>[http://dx.doi.org/10.1021/ja00290a017 Wilfried J. Mortier, Karin Van Genechten, Johann Gasteiger "Electronegativity equalization: application and parametrization", Journal of the American Chemical Society '''107''' pp. 829-835 (1985)]</ref> <ref>[http://dx.doi.org/10.1021/j100161a070 Anthony K. Rappe and William A. Goddard III "Charge equilibration for molecular dynamics simulations", Journal of Physical Chemistry '''95''' pp. 3358-3363 (1991)]</ref> is a technique for calculating the distribution of charges | ||
within a (large) molecule. This distribution can change with time to match changes in the local environment. | within a (large) molecule. This distribution can change with time to match changes in the local environment. | ||
==Electronegativity and electronic hardness== | |||
The atomic electronegativity is given by <ref>[http://dx.doi.org/10.1063/1.1749394 Robert S. Mulliken "A New Electroaffinity Scale; Together with Data on Valence States and on Valence Ionization Potentials and Electron Affinities", Journal of Chemical Physics '''2''' pp. 782-793 (1934)]</ref> | |||
:<math>\chi = \frac{\mathrm{IP + EA} }{2} \approx \frac{\partial E}{\partial Q}</math> | |||
where IP is the ionisation potential, and EA is the electron affinity. The electronic hardness is given by <ref>[http://dx.doi.org/10.1021/ja00364a005 Robert G. Parr and Ralph G. Pearson "Absolute hardness: companion parameter to absolute electronegativity", Journal of the American Chemical Society '''105''' pp. 7512-7516 (1983)]</ref> | |||
:<math>\eta = \mathrm{IP - EA} \approx \frac{\partial^2 E}{\partial Q^2} </math> | |||
==Charge equilibration potential energy== | |||
==Split-charge formalism== | ==Split-charge formalism== | ||
<ref>[http://dx.doi.org/10.1063/1.2346671 Razvan A. Nistor, Jeliazko G. Polihronov, Martin H. Müser, and Nicholas J. Mosey "A generalization of the charge equilibration method for nonmetallic materials", Journal of Chemical Physics '''125''' 094108 (2006)]</ref> | <ref>[http://dx.doi.org/10.1063/1.2346671 Razvan A. Nistor, Jeliazko G. Polihronov, Martin H. Müser, and Nicholas J. Mosey "A generalization of the charge equilibration method for nonmetallic materials", Journal of Chemical Physics '''125''' 094108 (2006)]</ref> | ||
==Fluctuating-charge formalism== | |||
====QTPIE==== | |||
<ref>[http://dx.doi.org/10.1016/j.cplett.2007.02.065 Jiahao Chen and Todd J. Martínez "QTPIE: Charge transfer with polarization current equalization. A fluctuating charge model with correct asymptotics", Chemical Physics Letters '''438''' pp. 315-320 (2007)]</ref> | |||
==References== | ==References== | ||
<references/> | <references/> | ||
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Charge equilibration (QEq) for molecular dynamics simulations [1] [2] is a technique for calculating the distribution of charges within a (large) molecule. This distribution can change with time to match changes in the local environment.
Electronegativity and electronic hardness
The atomic electronegativity is given by [3]
where IP is the ionisation potential, and EA is the electron affinity. The electronic hardness is given by [4]
Charge equilibration potential energy
Split-charge formalism
Fluctuating-charge formalism
QTPIE
References
- ↑ Wilfried J. Mortier, Karin Van Genechten, Johann Gasteiger "Electronegativity equalization: application and parametrization", Journal of the American Chemical Society 107 pp. 829-835 (1985)
- ↑ Anthony K. Rappe and William A. Goddard III "Charge equilibration for molecular dynamics simulations", Journal of Physical Chemistry 95 pp. 3358-3363 (1991)
- ↑ Robert S. Mulliken "A New Electroaffinity Scale; Together with Data on Valence States and on Valence Ionization Potentials and Electron Affinities", Journal of Chemical Physics 2 pp. 782-793 (1934)
- ↑ Robert G. Parr and Ralph G. Pearson "Absolute hardness: companion parameter to absolute electronegativity", Journal of the American Chemical Society 105 pp. 7512-7516 (1983)
- ↑ Razvan A. Nistor, Jeliazko G. Polihronov, Martin H. Müser, and Nicholas J. Mosey "A generalization of the charge equilibration method for nonmetallic materials", Journal of Chemical Physics 125 094108 (2006)
- ↑ Jiahao Chen and Todd J. Martínez "QTPIE: Charge transfer with polarization current equalization. A fluctuating charge model with correct asymptotics", Chemical Physics Letters 438 pp. 315-320 (2007)
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