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001-es BibID:	BIBFORM055539
Első szerző:	Dapprich, Stefan
Cím:	A new ONIOM implementation in Gaussian98. Part I. The calculation of energies, gradients, vibrational frequencies and electric field derivatives / Stefan Dapprich, István Komáromi, K. Suzie Byun, Keiji Morokuma, Michael J. Frisch
Dátum:	1999
ISSN:	0166-1280
Megjegyzések:	The IMOMM, IMOMO, and ONIOM methods have been proven to be powerful tools for the theoretical treatment of large molecular systems where different levels of theory are applied to different parts of a molecule. Within this framework we present a modified handling of the link atoms which are introduced to terminate the dangling bonds of the model system. Using this new scheme the definition of the combined energy gradient, the Hessian matrix, and the integration of higher derivatives of the energy with respect to nuclear coordinates and the electric field vector becomes straightforward. This allows for the first time the consistent combination of vibrational frequencies and the calculation of other molecular properties such as IR intensities, Raman intensities as well as dipole moments, polarizabilities, and hyperpolarizabilities. Test calculations for some typical as well as unusual examples and partitioning schemes are presented to demonstrate the power and limitations of the method and to provide guidelines for its applicability. Users of the method are strongly advised to test, calibrate and confirm for themselves the validity of the method combination and the model subsystem for the properties they want to calculate.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Journal of Molecular Structure-Theochem. - 461-462 (1999), p. 1-21. -
További szerzők:	Komáromi István (1957-) (vegyész, molekuláris biológus, biokémikus) Byun, K. Suzie Morokuma, Keiji Frisch, Michael J.
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001-es BibID:	BIBFORM040365
Első szerző:	Vreven, Thom
Cím:	Combining quantum mechanics methods with molecular mechanics methods in ONIOM / Vreven, T., Byun, K. S., Komaromi, I., Dapprich, S., Montgomery, J. A. Jr., Morokuma, K., Frisch, M. J.
Dátum:	2006
Megjegyzések:	The purpose of this paper is 2-fold. First, we present several extensions to the ONIOM(QM:MM) scheme. In its original formulation, the electrostatic interaction between the regions is included at the classical level. Here we present the extension to electronic embedding. We show how the behavior of ONIOM with electronic embedding can be more stable than QM/MM with electronic embedding. We also investigate the link atom correction, which is implicit in ONIOM but not in QM/MM. Second, we demonstrate some of the practical aspects of ONIOM(QM:MM) calculations. Specifically, we show that the potential surface can be discontinuous when there is bond breaking and forming closer than three bonds from the MM region.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Journal of Chemical Theory and Computation. - 2 : 3 (2006), p. 815-826. -
További szerzők:	Byun, K. Suzie Komáromi István (1957-) (vegyész, molekuláris biológus, biokémikus) Dapprich, Stefan Montgomery, John A. Jr. Morokuma, Keiji Frisch, Michael J.
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