Electron-Vibrational Interaction and Equilibrium Configurations of the Hydrogen Peroxide Molecule

We show that electron-vibrational interaction (Renner effect) in the model of linear configuration of the hydrogen peroxide molecule leads to removal of degeneracy of the electronic state and is the determining factor for the existence of two dissimilar nonplanar equilibrium symmetrically equivalent configurations.     

Calculation of intensities of torsional-rotational bands in the IR absorption spectrum of hydrogen peroxide

We present the calculated intensity distributions in torsional-rotational IR absorption bands of hydrogen peroxide. The torsional components of the band intensities have been calculated based on the appropriate matrix element computations. The contribution of the rotational components has been calculated using the 3j-symbols technique. The calculations have proved the reliability of available data on rotational constants, barrier heights of internal rotation, and locations of torsional-rotational levels of hydrogen peroxide. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 153–158, March–April, 2008.     

Fourth-Order Rotational Corrections to the Effective Dipole Moments of Nonrigid Asymmetric Rotors

An expression for the fourth-order rotational correction terms of the effective dipole moments of nonrigid asymmetric rotors has been derived using the method of contact transformation. The treatment takes into account the large-amplitude bending motion. The correction terms have been calculated for the different bending states of the H(2)O molecule. A poor convergence of the rotational series for this molecule has been obtained and some different nonpolynomial forms for these series, obtained by different summation methods, have been proposed and tested. Copyright 2001 Academic Press.     

光缔合产生超冷分子及其光谱测量

超冷分子的产生对于量子信息、分子物理和分子化学具有重要的意义。本文通过介绍超冷分子的研究进展,主要分析了光缔合产生超冷分子的特点与物理机制,详细介绍了光缔合产生冷分子过程中的光谱测量方法。     

Stability of Ground States of 2d Strongly Asymmetric Correlated-Hopping Hubbard Model

The asymmetric correlated-hopping Hubbard model is analysed perturbatively for large values of the Coulomb interaction U. An effective Hamiltonian is obtained up to terms of the order U ^–3. For d=2 and in the limit of the strong asymmetry, the orderings of the ground states are found (confirming earlier nonrigorous results). Their thermal and quantum stability is proved. These results have been obtained by an application of the quantum Pirogov–Sinai theory in the variant developed by Datta, Fernandez, Fröhlich, and Rey-Bellet.     

The Pauli Principle and the Restricted Primitive Model

The restricted primitive model is an electrically neutral, classical model consisting of hard spheres charged either +q or –q. We show that, by appropriately selecting the diameter of the hard spheres, the pressure when q=0 can be made equal to that for a fluid of Maxwell–Boltzmann point ions and an ideal Fermi gas of electrons. We compare the series expansion of these classical and quantum systems and find that, except for intermediate de Broglie density and moderate to strong electrical interaction strength, the restricted primitive model gives a reasonable representation of the pressure of the corresponding quantum system. Much of the current interest, however, has been focused on the above, excepted region.     

Calculation and Analysis of the IR Spectra of Cytosine in Various Phase States

Plane vibrations and intensities of the IR spectra of the ketone and enol forms of cytosine and deuterocytosine in various phase states are calculated and analyzed. It is shown that in a crystalline state and an aqueous solution cytosine forms a hydrogen bond of two types: C₂=O₈...HN₁ and C₂=O₈...HN₁₀, with a stronger intermolecular interaction in both phases being implemented by the hydrogen bonds between the O₈ and N₁ atoms. A satisfactory interpretation of the spectrum of the isolated molecules of cytosine, with the simultaneously existing ketone and enol tautomeric forms, is possible in the presence of the structural isomers of the enol form that differ in the position of multiple bonds.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 2, pp. 149–156, March–April, 2005.     

Coefficients of Kinematic Interaction between Excited Vibrational States

Within the framework of an algebraic perturbation method for eigenvalues and eigenvectors and using a theory of projectors, the structure parameters of excited molecular vibrations are investigated. To do this, formulas for the higherorder elements of the vibrationform tensor have been obtained on the basis of which and in conformity with the order of the perturbation theory the changes in the intramolecular dynamic parameters and in the coefficients of the kinematic interaction between the excited vibrational states are determined.     

The torsion potential function of hydrogen peroxide and disulfan molecules

A method for constructing the torsion potential function of hydrogen peroxide and disulfan molecules which takes into account the magnitudes of intramolecular interactions is suggested. The new representation of the potential is used to calculate the torsion spectra of the molecules indicated. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 4, pp. 450–452, July–August, 2000.     

Rotational spectra of the deuterated carbon chain molecules: C3D, C4D, C3HD, and C4HD

The rotational spectra of the deuterated carbon chain molecules, C₃D, C₄D, C₃HD, and C₄HD, have been measured with the Fourier transform microwave (FTMW) spectrometer. The C₃D and C₄D radicals are produced by discharging the DCCD gas diluted in Ar. On the other hand, the gaseous mixture of HCCH, DCCD, and HCCD diluted in Ar is used for producing C₃HD and C₄HD. For C₃D, the molecular constants are determined from a joint least-squares analysis with the previously published millimeter- and submillimeter-wave data by considering the vibronic interaction between the ²Π ground state and the low-lying ²Σ vibronic state. The molecular constants of C₄D are determined by use of the conventional Hamiltonian of the ²Σ radical, while the effective rotational constant and centrifugal distortion constant are derived for C₃HD and C₄HD. In the present study, the hyperfine interaction constants of the deuterium nuclei in C₃D and C₄D are determined accurately. In particular, the nuclear quadrupole interaction constant, eQq, of the C₃D radical is found to be significantly smaller than those of C₂D and C₄D, indicating that C₃D has a floppy motion of the CCD bending mode due to the large Renner-Teller effect.     

Method of configuration interaction in calculations of the spectral characteristics of atoms and molecules

For He, Be, Ne, and Mg atoms and their isoelectronic series, calculations of the dipole dynamic polarizability, energies, and strengths of the oscillators of the lowest electronic transitions are made within the scope of the method of configuration interaction. This very method is also used to calculate the dipole dynamic polarizability of a number of molecules of hydrides and N₂ and CO₂ molecules. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 4, pp. 427–432, July–August, 2000.     

解除氢原子能级(n=3)的简并

讨论氢原子能级在两个正交线性非均匀电场中的分裂。     

On the transferability of atomic contributions to the optical rotatory power of hydrogen peroxide,methyl hydroperoxide and dimethyl peroxide

The chirality of molecules expresses itself, for example, in the fact that a solution of a chiral molecule rotates the plane of linear polarised light. The underlying molecular property is the optical rotatory power (ORP) tensor, which according to time-dependent perturbation theory can be calculated as mixed linear response functions of the electric and magnetic dipole moment operators. Applying a canonical transformation of the Hamiltonian, which reformulates the magnetic dipole moment operator in terms of the operator for the torque acting on the electrons, the ORP of a molecule can be partitioned into atomic and group contributions. In the present work, we investigate the transferability of such individual contributions in a series of small, chiral molecules: hydrogen peroxide, methyl hydroperoxide and dimethyl peroxide. The isotropic atomic or group contributions have been evaluated for the hydrogen, oxygen and carbon atoms as well as for the methyl group at the level of time-dependent density functional theory with the B3LYP exchange-correlation functional employing a large Gaussian basis set. We find that the atomic or group contributions are not transferable among these three molecules.     

A Theoretical Study of a Single-Walled ZnO Nanotube as a Sensor for H_2 O Molecules

We have studied the property of single-walled ZnO nanotubes with adsorbed water molecules, and theoretically designed a new sensor for detecting water molecules using single-walled ZnO nanotubes using a combination of density functional theory and the non-equilibrium Green's function method. Details of the geometric structures and adsorption energies of the H 2 O molecules on the ZnO nanotube surface have been investigated. Our computational results demonstrate that the formation of hydrogen bonding between the H 2 O molecules and the ZnO nanotube, and adsorption energies of the H 2 O molecules on the ZnO nanotube are larger than the adsorption energies of other gas molecules present in the atmospheric environment. Moreover, the current-voltage curves of the ZnO nanotube with and without H 2 O molecules adsorbed on its surface are calculated, the results of which showed that the H 2 O molecules form stable adsorption configurations that could lead to the decrease in current. These results suggest that the single-walled ZnO nanotubes are able to detect and monitor the presence of H 2 O molecules by applying bias voltages.     

Molecular Modeling of Polyisobutylene. Application of the Modified Rotational Isomeric States Model for Polymers Comprising Four Rotational Isomeric States

Due to the presence of two alternating bond angles in the backbone of the polymeric chains, polyisobutylene (PIB) possesses four different rotational isomeric states. Accordingly, conformations of PIB could be represented by a four-state rotational isomeric scheme with only one adjustable statistical weight parameter. Rotational isomeric states (RIS) were determined at +25°, ?25°, +120°, ?120°. Conformations were divided into a “+class” and “?class,” with bond conformations tended to be followed by those from the same class and with changes from one class to the other rare. Since the configurational and thermodynamic properties of PIB depend to a great deal on the conformational characteristics of the polymer, a modified rotational isomeric state approximation was used to generate the initial configurations of the polymeric chains without allowing for any segment-segment overlap. Attempts were made to test the configurational properties of these systems against those determined experimentally to ensure that these configurations do represent realistically the polymeric system. Furthermore, these configurations were used to perform subsequent molecular dynamics runs to elucidate the effect of the molecular weight of the polymer and the temperature on some of its important thermodynamic properties, such as self-diffusion coefficient, thermal pressure coefficient, heat capacity, and dielectric constant.     

Rotational and Torsional Analysis of the OH-Stretch Third Overtone in CH3OH

We record double resonance spectra of the 4ν₁ band of jet-cooled ¹³C-methanol using single rotational state selection in the ν₁ fundamental and subsequent promotion of the selected molecules to the fourth vibrational level. We then detect transitions to the final excited states by infrared laser assisted photofragment spectroscopy (IRLAPS). The assigned A symmetry transitions reach upper states with K=0 and 1, and J from 0 to 5. For E symmetry, the transitions reach levels with K in the range −3 to 2 and J from 1 to 7. The rotation-torsional analysis determines a value for the torsional tunneling splitting of 2.8±0.4 cm⁻¹ at v₁=4. In a previous paper (J. Chem. Phys.110, 11 359-11 367 (1999)), we reported a trend of monotonically decreasing tunneling splittings in ¹²CH₃OH for v₁=0, 3, and 6 that we explained by a model that incorporates a linear increase in the torsional barrier height with OH stretch excitation. The ¹³CH₃OH tunneling splitting for the 4ν₁ band is in quantitative agreement with the trend found for ¹²CH₃OH.     

均匀磁场中氢原子低能级简并度的解除

讨论了均匀强磁场中氢原子哈密顿量中B^2项的影响,指出在忽略自旋－轨道相互作用的情况下,该项可使氢原子低能级简并度完全解除。     

On the Fluorescence Depolarization and the Calculation of Rotational Relaxation Times of Rigid Rod Molecules

The rotational relaxation times of rod like molecules like poly[arylene-ethynylene]s and their low molecular weight model compounds calculated from a simple model agree well with the experimental ones as long as the axial ratio of the corresponding rotational ellipsoid is less than 8. For the polymer (axial ratio > 10) the fluorescence depolarization cannot be described by rotational motion perpendicularly to the long molecular axis. One has to take into consideration bending motions in connection with energy transfer along the bent backbone.     

氢原子斯塔克效应中微扰矩阵元的普遍公式

讨论了任意能级下氢原子斯塔克效应中的微扰矩阵元,并给出了n=4能级的能量一级修正值。