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101.
C. Xia 《Journal of Molecular Spectroscopy》2005,229(1):39-46
The CO-stretching vibration-rotation spectra of CO-H2S, CO-D2S, and CO-HDS complexes have been studied in the 2150 cm−1 region using a supersonic slit-jet expansion and a tunable diode laser spectrometer. The spectra were analyzed with the help of very recent microwave pure rotational studies of the same complexes. Two bands were assigned for each of the symmetric hydrogen sulfide isotopes, corresponding to the two nuclear spin modifications, para and ortho. The band origins were blue shifted, relative to the free CO molecule, by about 3.8 cm−1 for CO-H2S and 4.3 cm−1 for CO-D2S. These are considerably smaller shifts than exhibited by the related CO-water complexes, indicating that the intermolecular forces in CO-H2S are weaker and more isotropic. 相似文献
102.
103.
Zheng Su 《Journal of Molecular Spectroscopy》2005,232(1):112-114
Rotational transitions of the propylene oxide-20Ne and propylene oxide-22Ne molecular adducts have been measured, in the frequency region from 4 to 18 GHz, using a pulsed jet Fourier Transform microwave spectrometer. The transition frequencies were used to refine the rotational and distortion spectroscopic constants obtained from the previous free jet millimetre wave measurements of the complex. No splittings due to the methyl group internal rotation were detected. 相似文献
104.
105.
Using the reaction‐relevant two‐dimensional potential energy surface, an accurate reaction‐pathway mapping and ab inito molecular dynamics, it is shown that CO2 capture by P(tBu)3 and B(C6F5)3 species has many nearly degenerate reaction‐routes to take. The explanation of that is in the topography of the transition state (saddle) area. An ensemble of asynchronous reaction‐routes of CO2 binding is described in fine detail. © 2013 Wiley Periodicals, Inc. 相似文献
106.
We propose an iterative method to solve some non-linear ordinary differential equations. Comparing on the Mathieu, van der Pol and Hill equation of fourth order, we see that this method is much more efficient than the well known methods by Lyapunov or Picard. 相似文献
107.
12 not so angry men: Hexaphenylethane is unstable, a phenomenon traditionally attributed to steric repulsion between the six phenyl rings. However, adding 12 bulky tert-butyl groups, one to each of the 12 meta positions, gives a stabile ethane derivative (see space-filling model and potential energy curve for the dissociation of the central C-C bond). This unexpected stabilization is shown to result from attractive dispersion interactions between the substituents. 相似文献
108.
The stability characteristics of an ultra-thin layer of a viscous liquid flowing down a cylindrical fibre are investigated by a linear theory. The film with the thickness less than 100 nm is driven by an external force and under the influence of the van der Waals forces. The results show that, when the relative film thickness decreases, the curvature of the fibre depresses the development of the linear perturbations, whereas the van der Waals forces promote the instabilities. This competition results in a non-monotonous dependence of the growth rate on the relative film thickness. The critical curves are also obtained to describe the transition from the absolute instability to the convective instability, indicating that the van der Waals forces can enlarge the absolutely unstable region. Furthermore, the surface tension can cause the development of the absolute instability, whereas the external force has an opposite effect. 相似文献
109.
Collision efficiency of two nanoparticles with different diameters in Brownian coagulation 总被引:1,自引:0,他引:1
The collision efficiency of two nanoparticles with different diameters in the Brownian coagulation is investigated. The collision
equations are solved to obtain the collision efficiency for the dioctyl phthalate nanoparticle with the diameter changing
from 100 nm to 750 nm in the presence of the van der Waals force and the elastic deformation force. It is found that the collision
efficiency decreases as a whole with the increase of both the particle diameter and the radius ratio of two particles. There
exists an abrupt increase in the collision efficiency when the particle diameter is equal to 550 nm. Finally, a new expression
is presented for the collision efficiency of two nanoparticles with different diameters. 相似文献
110.
Matthew J. Biller 《Molecular physics》2013,111(7):377-387
The interaction within the methane–methane (CH4/CH4), perfluoromethane–perfluoromethane (CF4/CF4) methane–perfluoromethane dimers (CH4/CF4) was calculated using the Hartree–Fock (HF) method, multiple orders of Møller–Plesset perturbation theory [MP2, MP3, MP4(DQ), MP4(SDQ), MP4(SDTQ)], and coupled cluster theory [CCSD, CCSD(T)], as well as the PW91, B97D, and M06-2X density functional theory (DFT) functionals. The basis sets of Dunning and coworkers (aug-cc-pVxZ, x?=?D, T, Q), Krishnan and coworkers [6-311++G(d,p), 6-311++G(2d,2p)], and Tsuzuki and coworkers [aug(df, pd)-6-311G(d,p)] were used. Basis set superposition error (BSSE) was corrected via the counterpoise method in all cases. Interaction energies obtained with the MP2 method do not fit with the experimental finding that the methane–perfluoromethane system phase separates at 94.5?K. It was not until the CCSD(T) method was considered that the interaction energy of the methane–perfluoromethane dimer (?0.69?kcal?mol?1) was found to be intermediate between the methane (?0.51?kcal?mol?1) and perfluoromethane (?0.78?kcal?mol?1) dimers. This suggests that a perfluoromethane molecule interacts preferentially with another perfluoromethane (by about 0.09?kcal?mol?1) than with a methane molecule. At temperatures much lower than the CH4/CF4 critical solution temperature of 94.5?K, this energy difference becomes significant and leads perfluoromethane molecules to associate with themselves, forming a phase separation. The DFT functionals yielded erratic results for the three dimers. Further development of DFT is needed in order to model dispersion interactions in hydrocarbon/perfluorocarbon systems. 相似文献