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Masao Masamura 《Structural chemistry》2000,11(1):41-45
The purpose of this article is to show that CHELP, CHELPG, and Merz and Kollman undergo error for the charge on atoms of HCOO– (H2O)
n
for n = 1 6. We also demonstrate that the CHELP, CHELPG, and Merz and Kollman show error for the tendency toward change in the charges on carbons for CH3NH+
3 (CH3)2NH+
2 (CH3)3NH+ (CH3)4N+. 相似文献
2.
Masamura Shinnosuke Iwamoto Tetsu Sugitani Yoshiki Konishi Keiji Hara Naoyuki 《Nonlinear dynamics》2020,99(4):3155-3168
Nonlinear Dynamics - The present study experimentally investigates amplitude death in delay-coupled double-scroll circuits with a time-varying network topology that randomly changes at a regular... 相似文献
3.
Masao Masamura 《Journal of computational chemistry》2001,22(1):125-131
The purpose of this study was to calculate the structures and energetics of CH3OH$_{2}^{+}$(H2O)n and CH3SH$_{2}^{+}$(H2O)n in the gas phase: we asked how the CH3OH$_{2}^{+}$ and CH3SH$_{2}^{+}$ moieties of CH3OH$_{2}^{+}$(H2O)n and CH3SH$_{2}^{+}$(H2O)n change with an increase in n and how can we reproduce the experimental values ΔH°n−1,n. For this purpose, we carried out full geometry optimizations with MP2/6‐31+G(d,p) for CH3OH$_{2}^{+}$(H2O)n (n=0,1,2,3,4,5) and CH3SH$_{2}^{+}$(H2O)n (n=0,1,2,3,4). We also performed a vibrational analysis for all clusters in the optimized structures to confirm that all vibrational frequencies are real. All of the vibrational frequencies of these clusters are real, and they correspond to equilibrium structures. For CH3OH$_{2}^{+}$(H2O)n, when n increases, (1) the C O bond length decreases, (2) the C H bond lengths do not change, (3) the O H bond lengths increase, (4) the OCH bond angles increase, (5) the COH bond angles decrease, (6) the charge on CH3 becomes less positive, and (7) these predicted values, except for the O H bond lengths of CH3OH$_{2}^{+}$(H2O)n, approach the corresponding values in CH3OH. The C O bond length in CH3OH$_{2}^{+}$(H2O)5 is shorter than that in CH3OH$_{2}^{+}$ in the gas phase by 0.061 Å at the MP2/6‐31+G(d,p) level. Except for the S H bond lengths in CH3SH$_{2}^{+}$(H2O)n, however, the structure of the CH3SH$_{2}^{+}$ moiety does not change with an increase in n. © 2000 John Wiley & Sons, Inc. J Comput Chem 22: 125–131, 2001 相似文献
4.
Masamura M 《Journal of computational chemistry》2004,25(14):1771-1778
The intermolecular interaction energies of the deprotonated hydrogen-bonded complexes F(-)(HF), F(-)(H(2)O), F(-)(NH(3)), Cl(-)(HF), SH(-)(HF), H(2)P(-)(HF), OH(-)(H(2)O), OH(-)(H(2)O)(2), OH(-)(NH(3)), Cl(-)(H(2)O), SH(-)(H(2)O), H(2)P(-)(H(2)O), Cl(-)(NH(3)), SH(-)(NH(3)), H(2)P(-)(NH(3)), Cl(-)(HCl), Cl(-)(H(2)S), Cl(-)(PH(3)), SH(-)(H(2)S), SH(-)(PH(3)), and H(2)P(-)(PH(3)) were calculated with correlation consistent basis sets at the MP2, MP4, QCISD(T), and CCSD(T) levels. When the basis set is smaller, the counterpoise-uncorrected intermolecular interaction energies are closer to the complete basis set limit than the counterpoise-corrected intermolecular interaction energies. The counterpoise-uncorrected intermolecular interaction energies obtained at the MP2/aug-cc-pVDZ level of theory are close to the interaction energies obtained at the extrapolated complete basis set limit in most of the complexes. Also, we investigate the accuracy of the other levels. 相似文献
5.
6.
Masao Masamura 《Theoretical chemistry accounts》2001,106(4):301-313
For the intermolecular interaction energies of ion-water clusters [OH−(H2O)
n
(n=1,2), F−(H2O), Cl−(H2O), H3O+(H2O)
n
(n=1,2), and NH4
+(H2O)
n
(n=1,2)] calculated with correlation-consistent basis sets at MP2, MP4, QCISD(T), and CCSD(T) levels, the basis set superposition
error is nearly zero in the complete basis set (CBS) limit. That is, the counterpoise-uncorrected intermolecular interaction
energies are nearly equal to the counterpoise-corrected intermolecular interaction energies in the CBS limit. When the basis
set is smaller, the counterpoise-uncorrected intermolecular interaction energies are more reliable than the counterpoise-corrected
intermolecular interaction energies. The counterpoise-uncorrected intermolecular interaction energies evaluated using the
MP2/aug-cc-pVDZ level is reliable.
Received: 14 March 2001 / Accepted: 25 April 2001 / Published online: 9 August 2001 相似文献
7.
The acoustic load dependency of the electroacoustic efficiency in the electrostrictive transducer is derived theoretically and measured experimentally. The results show that there is an optimum acoustic load resistance which maximizes the electroacoustic efficiency. It is considered reasonable to cite the optimum condition as ‘acoustical matching’ of the transducer to the acoustic load. 相似文献
8.
The purpose of this article was to calculate the structures and energetics of CH3O−(H2O)n and CH3S−(H2O)n in the gas phase; the maximum number of water molecules that can directly interact with the O of CH3O−; and when n is larger, we asked how the CH3O− and CH3S− moiety of CH3O−(H2O)n and CH3S−(H2O)n changes and how we can reproduce experimental ΔH 0n−1, n. Using the ab initio closed-shell self-consistent field method with the energy gradient technique, we carried out full geometry optimizations with the MP2/aug-cc-pVDZ for CH3O−(H2O)n (n=0, 1, 2, 3) and the MP2/6–31+G(d,p) (for n=5, 6). The structures of CH3S−(H2O)n (n=0, 1, 2, 3) were fully optimized using MP2/6–31++G(2d,2p). It is predicted that the CH3O−(H2O)6 does not exist. We also performed vibrational analysis for all clusters [except CH3O−(H2O)6] at the optimized structures to confirm that all vibrational frequencies are real. Those clusters have all real vibrational frequencies and correspond to equilibrium structures. The results show that the above maximum number of water molecules for CH3O− is five in the gas phase. For CH3O−(H2O)n, when n becomes larger, the C—O bond length becomes longer, the C—H bond lengths become smaller, the HCO bond angles become smaller, the charge on the hydrogen of CH3 becomes more positive, and these values of CH3O−(H2O)n approach the corresponding values of CH3OH with the n increment. The C—O bond length of CH3O−(H2O)3 is longer than the C—O bond length of CH3O− in the gas phase by 0.044 Å at the MP2/aug-cc-pVDZ level of theory. The structure of the CH3S− moiety in CH3S−(H2O)n does not change with the n increment. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 1138–1144, 1999 相似文献
9.
M. Masamura 《Theoretical chemistry accounts》1989,75(6):433-446
The purpose of this report is to quantitatively find the cause for the elongation of the R-C bond in R-COO– (R = H, CH3 and C2H5) and the shortening of the C-O bond in CH3-O– upon deprotonation in the gas phase. These elongations and shortenings result from the contributions of R–---CO2 and H–---CH2=O as resonance structures to the systems. Because these structures must make only a small contribution in the crystal, the R-C bond lengths of R-COO– (R= H and CH3) in the crystal structure are shorter than those in the gas phase. 相似文献
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