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81.
S. K. Godunov 《Siberian Mathematical Journal》1992,33(6):939-949
Novosibirsk. Translated fromSibirski Matematicheski Zhurnal, Vol. 33, No. 6, pp. 3–13, November–December, 1992. 相似文献
82.
The potential energy surfaces of the nitroso compounds CClF2NO and CCl2FNO in the ground and lowest excited singlet and triplet electronic states were studied by various ab initio methods (including multiconfigurational methods). The equilibrium geometric parameters, vibrational frequencies, internal rotation potential functions, and rotational contours of bands in the S1 S0 vibronic spectrum of the CClF2NO molecule were calculated. For the molecules under consideration, the quantum-mechanical problem on torsional motion was solved. The results of calculations are, on the whole, in good agreement with experiment. 相似文献
83.
84.
The structure of the conformationally nonrigid fluoral molecule (CF3CHO) in the ground (S0) and lowest excited triplet (T1) and singlet (S1) electronic states was studied by ab initio quantum-chemical methods. The equilibrium geometric parameters and harmonic vibrational frequencies of the molecule in these electronic states were determined. The calculations demonstrated that the electronic excitation causes substantial changes in the molecular structure involving the rotation of the CF3 top and the deviation of the CCHO carbonyl fragment from planarity. The quantum-mechanical problems for large-amplitude vibrations, namely, for the torsional vibration in the S0 state and the torsional and inversion vibrations (nonplanar carbonyl fragment) in the T1 and S1 states, were solved in the one- and two-dimensional approximations. A comparison of the results of calculations revealed the correlation between the torsional and inversion motions. 相似文献
85.
The vibronic absorption spectrum of chloral (CCl3COH) vapors is studied in the region of S1 ← S0 electron transition (32,000–28,700 cm−1). The 29,070 cm−1 vibronic transition (not observed because of low intensity) is believed to be the ‘start’ of the electron transition. Several
fundamentals are found in the S0 and S1 states. Inversion splitting of the zero vibrational level in the S1 state of chloral, indicating a nonplanar structure of the carbonyl fragment, is found. The intensity ratio of the torsional
transition bands indicates that the S1 ← S0 electronic excitation of the chloral molecule causes significant changes in the orientation of the −CCl3 group relative to the molecular framework. The potential functions of internal rotation (S0 and S1 states) and inversion (S1 state) of the chloral molecule are determined from experimental data. The potential barriers of internal rotation (S0 and S1 states) and inversion (S1 state) are 380, 780, and 760 cm−1 (4.5, 9.3, and 9.1 kJ/mole), respectively.
M. V. Lomonosov Moscow State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 3, pp. 507–513, May–June, 1998. 相似文献
86.
Vapor-state absorption spectra have been recorded for acetyl fluoride and acetyl chloride and also for deuterated derivatives with path lengths up to 40 m. The origins of the S1S0 transitions have been derived, together with the torsional-vibration energy levels in the ground state S0 and excited singlet state S1. Fitting the calculated and observed rotational contours of the vibronic bands has been used to estimate the geometrical parameters in the S1 states. The carbonyl groups in the S1 states are nonplanar. The internal-rotation potentials have been determined for acetyl fluoride and acetyl chloride in the S1 and S0 states. The relative intensities of the torsional transitions in those states indicate that the minima in the potential energy are appreciably displaced along the torsional coordinate in the S0 and S1 states.Chemical Faculty, Lomonosov Moscow University. Translated from Zhurnal Strukturnoi Khimii, Vol. 34, No. 1, pp. 26–30, January–February, 1993. 相似文献
87.
We present a theoretical investigation of oxalyl fluoride (COF)2 in the ground and the four lowest excited (two singlet and two triplet) electronic states of the n,π∗-type mainly with the CASPT2(8-6)/cc-pVTZ method. Geometries, vibrational frequencies, potential energy functions of internal rotation, and adiabatic electronic transition energies were obtained. The conformer energy difference and the barrier to internal rotation in the ground electronic state were extrapolated to the complete basis set limit. The planar trans and cis conformations were the most stable configurations for all five electronic states under study. We found that the allowed electronic transition of the cis conformer has a transition energy that is significantly higher than that predicted in previous studies. For the excited states, the internal rotation was found to be accompanied by significant non-planar distortion of both carbonyl fragments, indicating strong coupling between these molecular motions. 相似文献
88.
We calculate the gravitational correction to the phase difference between neutrino mass eigenstates for the spherically symmetric
gravitational field described by the Schwarzschild metric. This correction was calculated in a number of works, but the results
of these works differ from each other. Our result does not coincide with the results ever published. In this work, we make
calculations in the simplest way and verify our result by several tests. 相似文献
89.
We calculate the Clebsch–Gordan coefficients for orthogonal rather than unitary representations of the rotation group. 相似文献
90.
S. K. Godunov A. F. Demchuk N. S. Kozin V. I. Mali 《Journal of Applied Mechanics and Technical Physics》1974,15(4):526-529
The purpose of this study is the construction of interpolation formulas for the dependence of Maxwell viscosity, a quantity which is the reciprocal of shear-strain relaxation time , on shear-strain intensity and temperature for several metals: iron, aluminum, copper, and lead. This function was interpolated in various temperature and deformation velocity ranges in accordance with available experimental data for iron (0 107 sec–1, 200 ° T 1500 °); aluminum (0 107 sec–1, 300 ° T 900 °); copper (0 105 sec–1, 300 ° T 1300 °); lead (0 106 sec–1, 90 ° T 400 °); temperatures in °K.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 4, pp. 114–118, July–August, 1974. 相似文献