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Counterpoise Method (counterpoise + method)
Selected AbstractsTheoretical investigation of charge transfer excitation and charge recombination in acenaphthylene,tetracyanoethylene complexINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 1 2003Hai-Bo Yi Abstract Ab initio calculations were performed to investigate the charge separation and charge recombination processes in the photoinduced electron transfer reaction between tetracyanoethylene and acenaphthylene. The excited states of the charge-balanced electron donor,acceptor complex and the singlet state of ion pair complex were studied by employing configuration interaction singles method. The equilibrium geometry of electron donor,acceptor complex was obtained by the second-order Mřller,Plesset method, with the interaction energy corrected by the counterpoise method. The theoretical study of ground state and excited states of electron donor,acceptor complex in this work reveals that the S1 and S2 states of the electron donor,acceptor complexes are excited charge transfer states, and charge transfer absorptions that corresponds to the S0 , S1 and S0 , S2 transitions arise from ,,,* excitations. The charge recombination in the ion pair complex will produce the charge-balanced ground state or excited triplet state. According to the generalized Mulliken,Hush model, the electron coupling matrix elements of the charge separation process and the charge recombination process were obtained. Based on the continuum model, charge transfer absorption and charge transfer emission in the polar solvent of 1,2-dichloroethane were investigated. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 94: 23,35, 2003 [source] Theoretical study of the prion protein based on the fragment molecular orbital methodJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 16 2009Takeshi Ishikawa Abstract We performed fragment molecular orbital (FMO) calculations to examine the molecular interactions between the prion protein (PrP) and GN8, which is a potential curative agent for prion diseases. This study has the following novel aspects: we introduced the counterpoise method into the FMO scheme to eliminate the basis set superposition error and examined the influence of geometrical fluctuation on the interaction energies, thereby enabling rigorous analysis of the molecular interaction between PrP and GN8. This analysis could provide information on key amino acid residues of PrP as well as key units of GN8 involved in the molecular interaction between the two molecules. The present FMO calculations were performed using an original program developed in our laboratory, called "Parallelized ab initio calculation system based on FMO (PAICS)". © 2009 Wiley Periodicals, Inc. J Comput Chem 2009 [source] Efficiency of numerical basis sets for predicting the binding energies of hydrogen bonded complexes: Evidence of small basis set superposition error compared to Gaussian basis setsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 2 2008Yasuji Inada Abstract Binding energies of selected hydrogen bonded complexes have been calculated within the framework of density functional theory (DFT) method to discuss the efficiency of numerical basis sets implemented in the DFT code DMol3 in comparison with Gaussian basis sets. The corrections of basis set superposition error (BSSE) are evaluated by means of counterpoise method. Two kinds of different numerical basis sets in size are examined; the size of the one is comparable to Gaussian double zeta plus polarization function basis set (DNP), and that of the other is comparable to triple zeta plus double polarization functions basis set (TNDP). We have confirmed that the magnitudes of BSSE in these numerical basis sets are comparative to or smaller than those in Gaussian basis sets whose sizes are much larger than the corresponding numerical basis sets; the BSSE corrections in DNP are less than those in the Gaussian 6-311+G(3df,2pd) basis set, and those in TNDP are comparable to those in the substantially large scale Gaussian basis set aug-cc-pVTZ. The differences in counterpoise corrected binding energies between calculated using DNP and calculated using aug-cc-pVTZ are less than 9 kJ/mol for all of the complexes studied in the present work. The present results have shown that the cost effectiveness in the numerical basis sets in DMol3 is superior to that in Gaussian basis sets in terms of accuracy per computational cost. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008 [source] Reply to "Comment on Aromatic-Backbone Interactions in Model ,-Helical Peptides"JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 1 2008József Csontos Abstract In response to Van Mourik's comments on our paper (J Comput Chem 2007, 28, 1208.) we present an extended version of our rotation method. We also prove that intramolecular interaction energies as well the basis set superposition errors calculated with our rotation method are comparable with those obtained by the counterpoise method of Boys and Bernardi (Mol Phys 1970, 19, 533). In intramolecular interaction energy calculations, if the interacting groups are in proximity, our rotation method is recommended to avoid artificial interactions, which can be induced by fragmentation. © 2007 Wiley Periodicals, Inc.J Comput Chem, 2008 [source] | ||||||||||