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The isomers of the carbonyl sulfide (OCS) molecule are investigated in detail at CCSD(T)/cc-pVTZ//MP2/6-311++G(2d,2p) level of theory. One cyclic isomer was identified along with three different linear minima of the OCS molecule. Three interconversion transition states were also located between cyclic and linear forms of OCS. Among these four isomers, the singlet potential energy surface (PES) for the molecule–molecule reaction between the three most energetically favoured isomers of OCS and H2O has been explored theoretically at the CCSD(T)/cc-pVTZ//MP2/6-311++G(2d,2p) level. This singlet PES comprises of three paths. Path 1 is the reaction of linear OCS molecule with water producing the major product P1 (CO2?+?H2S), minor product P2 (S?+?HCOOH) and two isomers via 14 minima and 15 transition states. The Path 2 is an isomerization process in which cyclic isomer of OCS reacts with water molecule via another initial barrierless aduct producing five isomers of the OCS–H2O system through five interconversion transition states. The reaction of linear COS isomer with water is shown in Path 3. This path produces the radicals SH and COOH from another COS–H2O complex via a transition state. Among these three products, the product P1 is energetically most favoured. The overall exothermicity of the product channels for the formation of major product P1 on PES is calculated to be about 10.60?kcal/mol possessing initial high entrance barriers of 45.48 and 55.47?kcal/mol in two possible pathways. As the process is favoured thermodynamically but not kinetically, the reaction is expected to be very slow. 相似文献
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应用群论及原子分子反应静力学方法推导Si分子的电子态及其离解极限,在B3P86/CC-PVTZ水平上,对Si3分子基态进行优化计算,得出Si3基态的单重态能量最低,其稳定构性为的C2V构型,平衡核间距Re=0.2176nm、∠213=79.7°,能量为-869.2057a.u..同时计算出基态的简正振动频率:对称伸缩振动频率ν(B2)=547.6446cm-1,弯曲振动频率ν(A1)=185.6100cm-1和反对称伸缩振动频率ν(A1)=559.6090cm-1.在此基础上,使用多体项展式理论方法,导出了基态Si3分子的全空间解析势能函数,该势能函数准确再现了Si3(C2V)平衡结构. 相似文献
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Yu. P. Morozova O. M. Zharkova T. Yu. Balakina V. Ya. Artyukhov B. V. Korolev 《Russian Physics Journal》2011,54(5):594-600
The fluorescent probe molecule – laurdan (6-dodekanoil-2-dimetilamin naphthalene) – is investigated by experimental and quantum-chemical
methods. The influence of the structure non-rigidity on the dipole moments, arrangement of energy levels, and distribution
of charges in the laurdan molecule is studied. An optimized structure is obtained and analyzed by the molecular dynamics method.
Several structures with different rotation angles of the dimethylamino group are investigated, for which energy, oscillator
forces, and nature of electron states are calculated. Fluorescence spectra of the laurdan molecule in an inert solvent are
interpreted. Centers of possible interaction of the molecule with a proton-donor solvent are established. Rate constants of
radiative and nonradiative processes and quantum fluorescence yields of the examined probe are calculated. 相似文献
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利用半经典量子化理论和量子理论,分别采用Lennard-Jones势和Morse势,对双原子分子的振动能级给予了较为详细的数值计算。并将所得结果与部分实验数据进行比较,峄双原子分子的振动能级作了较为详细的 讨论。 相似文献
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C.J. Allan U. Gelius D.A. Allison G. Johansson H. Siegbahn K. Siegbahn 《Journal of Electron Spectroscopy and Related Phenomena》1973,1(2):131-151
The core level electron spectra of CO2, CS2 and COS excited by Mg Kα radiation have been studied to identify shake-up satellite lines associated with ionization from these levels. A number of such lines have been seen and possible assignments have been suggested using the excited states of the molecule as a guide. The valence spectra have also been recorded and they too were found to be rich in shake-up structure. The observed variation of the valence line intensities is discussed and compared with predictions made from an intensity model. The validity of distinguishing between π and σ symmetries in linear molecules in applying the intensity model is confirmed. 相似文献
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应用群论及原子分子反应静力学方法推导了SiO2分子的电子态及其离解极限,采用B3P86方法,在6-311G**水平上,优化出SiO2基态分子稳定构型为单重态的C2V构型,其平衡核间距Re=RSi—O=0.1587 nm,∠OSiO=111.2°,能量为-440.4392 a.u..同时计算出基态的简正振动频率:对称伸缩振动频率ν(B2)=945.4cm-1,弯曲振动频率ν(A1)=273.5 cm-1和反对称伸缩振动频率ν(A1)=1362.9cm-1.在此基础上,使用多体项展式理论方法,导出了基态SiO2分子的全空间解析势能函数,该势能函数准确再现了SiO2(C2V)平衡结构. 相似文献
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The three-dimensional vibrational problem for the isolated van der Waals complex formed by the Li+ cation with the N2 molecule is solved by the variational method. The potential energy and dipole moment surfaces are calculated using different basis sets of atomic functions and different approaches for taking electron correlation into account. The anharmonic effects caused by the interaction of vibrational degrees of freedom of the complex are consistently considered for the first time. The energy levels of three-dimensional vibrational states are determined. The frequency shift of the N2 molecule vibration upon complexation and the fundamental transition intensity for this vibration in the complex are calculated. The frequencies and intensities for a number of spectral transitions between the states associated with excitation of low-frequency modes are determined. The average values of geometrical parameters and their variances are calculated for the ground state and excited vibrational states of the complex. 相似文献
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The rotational energy levels up to J,K?10 are calculated for the lowest vibrational state of the water molecule. A rapidly convergent model of the effective rotational Hamiltonian is used. 相似文献
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The complete spectroscopic assignment of calculated Partridge-Schwenke rotational energy levels up to J, K
a
= 30 is presented for the 000, 010, 100, 020, and 001 vibrational states of the D2
16O molecule. The nonpolynomial model of an effective rotational Hamiltonian is used to perform the assignment and to analyze
the experimental energy levels available in the literature for these states. The results obtained are compared with the data
calculated by other authors. The results of this study can be useful in searching for and identifying new, highly excited
rotational levels of D2
16O, as well as in creating the databases of parameters of rovibrational transitions of the water molecule. 相似文献
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Stephan Jan Bachmann 《Molecular physics》2014,112(21):2761-2780
The properties of water at physiological conditions can be modelled at different levels of resolution: (1) sub-atomic models that take into account electronic degrees of freedom, (2) atomic models that only account for atomic degrees of freedom and (3) supra-molecular models that only involve some supra-molecular degrees of freedom. To enhance the computational efficiency of molecular simulation, models at different levels of resolution should be simultaneously usable for different parts of a system for which the level of detail of interest is different. This requires these different types of models to be compatible with each other. In the present study, the compatibility of two polarisable models for liquid water, COS/G2 and COS/D, with a non-polarisable model for liquid water, SPC, is investigated. It is shown that these models are compatible. The polarisable models can thus be used to solvate biomolecules described by a biomolecular force field that is compatible with the SPC water model. 相似文献
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A. P. Golovitskii 《Technical Physics》2000,45(5):532-537
The cross section of electron attachment to chlorine molecules was calculated with the Condon reflection method for various populations of vibrational levels of the ground molecule state. The populations are defined by a prescribed vibrational temperature. The vibrational wave functions were obtained by numerically solving the Schrödinger equation, and required parameters of the potentials of upper ion states were taken, so as to minimize the deviation between calculated and room-temperature experimental data on the cross section of electron attachment. 相似文献
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O. K. Voitsekhovskaya D. E. Kashirskii V. S. Korchikov 《Moscow University Physics Bulletin》2010,65(5):386-391
The values of Dunham constants are calculated for the electronic ground state of the carbon monoxide molecule on the basis
of new values of the effective rotational and centrifugal constants and the energies of the high vibrational-rotational states
are predicted. The peculiarity of the approach consists in the use of vibrational-rotational levels computed according to
the traditional polynomial equation of energy values as the initial data for the procedure of Dunham coefficients determination.
The role of the maximum degree of the Dunham polynom in determining its coefficients is analyzed, and the energy levels up
to ν = 40 and J = 60 are calculated. A comparison with the literature data is made. 相似文献
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J.P.D. Cook M.G. White C.E. Brion W. Domcke J. Schirmer L.S. Cederbaum W. von Niessen 《Journal of Electron Spectroscopy and Related Phenomena》1981,22(3):261-270
The valence shell binding energy spectrum of carbonyl sulphide (10–45 eV) has been measured using both binary (e,2e) and dipole (e,2e) electron impact spectroscopy and calculated by the 2ph-TDA many body Green's function technique. The spectrum shows extensive structure above 20 eV, indicating a major breakdown of the quasi-particle picture for ionization of COS. The calculation is in good agreement with the present experimental and literature ESCA binding energy spectra. Binary (e,2e) spectra at two azimuthal angles support the theoretical prediction that this extensive final ion state structure arises primarily from ionization of the COS 6σ and 7σ inner valence electrons. 相似文献
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本文使用完全活性空间自洽场/多组态相互作用 (CAS SCF/MRCI)理论, 以cc-pVDZ 为基组,计算了NO分子基态(X2Π)和激发态 (a4П and B2П)的平衡结构和单点能扫描曲线.采用最小二乘法拟合了Murrell-Sorbie函数, 得到了NO分子的解析势能曲线,并利用Rydberg-Klein-Rees方法,计算得到的NO分子相应态的谐振频率和其它的光谱数据(ωe、αe、ωeχe、 βe)与实验值十分一致,和其它理论计算方法进行比较,发现该方法有更好的准确性. 以得到的解析势能函数为基础, 求解NO分子核运动的一维径向Schrdinger方程, 获得了更高振动态的振动能级. 相似文献
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采用从头算的多参考组态相互作用(MRCI)方法并结合基组aug-cc-pCVQZ计算了CO分子基态(X1Σ+)的势能曲线和偶极矩曲线,得到的势能曲线、偶极矩曲线分别与RKR势、文献的偶极矩曲线吻合较好。利用所得的势能,求解双原子分子核运动的Schrdinger方程找到了CO分子X1Σ+态转动量子数J=0时的70个振动态,对于每一振动态,分别计算了其振动能级G(v)、转动惯性常数Bv和离心畸变常数Dv,并把计算结果与已知的42个实验值做了详细比较,结果表明,计算的振动能级G(v)、转动惯性常数Bv、离心畸变常数Dv与实验值符合较好。利用G(v),Bv导出的光谱常数[谐振频率ωe(2 160.1 cm-1)、非谐振频率ωeχe(13.1 cm-1)、转动常数Be(1.918 cm-1)、振转耦合常数αe(0.017 3 cm-1)]也与实验值的光谱常数[ωe(2 169.8 cm-1),ωeχe(13.3 cm-1),Be(1.931 cm-1),αe(0.017 5 cm-1)]较为符合,这在一定程度上证明了方法MRCI/Aug-cc-pCVQZ对CO分子基态性质的计算是合适而可靠的。利用乘积近似方法计算了CO分子在常温、中温、高温时的配分函数,在此基础上,计算了CO分子在T=296 K时的1-0跃迁带的谱线强度,通过比较发现,计算所得的线强度与HITRAN数据库符合较好。进一步计算的CO分子X1Σ+态1-0,2-0,3-0,4-0,2-1,3-1和4-1跃迁带的带强度也与实验值较为吻合,同时首次计算了CO分子X1Σ+态3-2跃迁带、4-2跃迁带的线强度及带强度。 相似文献
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V. K. Konyukhov 《Bulletin of the Lebedev Physics Institute》2007,34(5):154-158
A theoretical explanation is proposed for the effect of variations in concentration of water molecule spin isomers in the gas phase during the interaction of molecules with a solid adsorbent surface. The explanation is based on antisymmetric (AS) correlation between proton spin moments and molecule rotation. A new AS correlation occurs during the interaction of the molecule with a dc electric field near the surface. Due to the new (external) AS correlation, ortho-and parawater molecules are formed; separation into spin modifications occurs over degenerate states of each rotational level of the molecule. Water molecule separation into spin modifications at the previous (internal) AS correlation occurs over rotational levels of molecules. The ratio of ortho-and parawater concentrations in the gas phase at the external AS correlation is compared with experimental data on chromatographic separation of water spin isomers. Quantitative agreement is observed between the calculated ratio and the ratio measured for water molecules at the final separation stage. 相似文献
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本文使用完全活性空间自洽场/多组态相互作用(CASSCF/MRCI)理论,以cc-pVDZ为基组,计算了NO分子基态(X2Π)和激发态(a4ПandB2П)的平衡结构和单点能扫描曲线.采用最小二乘法拟合了Murrell-Sorbie函数,得到了NO分子的解析势能曲线,并利用Rydberg-Klein-Rees方法,计算得到的NO分子相应态的谐振频率和其它的光谱数据(ωe、αe、ωeχe、βe)与实验值十分一致,和其它理论计算方法进行比较,发现该方法有更好的准确性.以得到的解析势能函数为基础,求解NO分子核运动的一维径向Schrdinger方程,获得了更高振动态的振动能级. 相似文献