A Method for the Precise Determination of the Intramolecular Potential Energy Surface on the Basis of Microwave and Submillimeter-Wave Spectra: Diatomic Molecules as a Relevant Illustration.

A new method for the precise semiempirical determination of the basic parameters (structural parameters and parameters of the intramolecular potential energy surface, PES) of a molecule on the basis of highly accurate experimental data from the microwave and submillimeter-wave regions is suggested. The options and advantages of this method in comparison with the other methods of molecular PES determination are discussed using a diatomic molecule as an appropriate illustration. The HCl molecule is exploited as a suitable example.

Comprehensive high resolution study of the SiH(M=28,29,30) tetradecad stretching bands: Appearance and applications of the isotopic substitution effect in molecules of spherical symmetry.

A set of new relations between different spectroscopic parameters of the high symmetry XY spherical top molecules is derived on the basis of the general isotopic substitution theory, and a comprehensive high accurate analysis of the five stretching bands (the bands ν+ν(F), 2ν(F), 2ν(E), 2ν(A), and 2ν(A); the three latter ones are forbidden in absorption) of the tetradecad of the SiH molecule is made. The high resolution spectra of SiH(M=28,29,30) in their natural abundance were recorded with a Bruker IFS125 HR Fourier transform infrared spectrometer at the Technische Universität Braunschweig, Germany with an optical resolution of 0.003 cm and theoretically analyzed (in this case, for the first time both for all five bands of the SiH and SiH species, and for 2ν(E), 2ν(A) bands of the SiH one).

Improved Theory of the Effective Dipole Moments and Absolute Line Strengths of the XY Asymmetric Top Molecules in the Doublet Electronic States.

A new effective dipole moment model for the XY (C2v-symmetry) molecule in a doublet electronic state is derived that includes (as special cases) all currently known models of effective dipole moments for such types of molecules, and allows us to take into account the influence of spin-rotation interactions on the effective dipole moment operator that were not considered in the preceding studies. Necessary for the analysis of absolute line strengths, the matrix elements of this dipole moment operator are derived. A comparison with the previous analog models is made and discussed.

Effective Dipole Moment Model for Axially Symmetric Molecules: Application to the Precise Study of Absolute Line Strengths of the Fundamental of CHCl.

The effective dipole moment model for molecules of axial C3v symmetry is derived on the basis of the symmetry properties of a molecule which, on the one hand, is of the same order of efficiency (but much simpler and clearer in applications) as the analogous models derived on the basis of the irreducible tensorial sets theory, and, on the other hand, mathematically more correct in comparison with concepts like the Herman-Walles function used in the models. As an application of the general results obtained, we discuss high-resolution infrared spectra of CH335Cl, recorded with the Zürich prototype ZP2001 (Bruker IFS125 HR) Fourier transform infrared spectrometer at a resolution of 0.001 cm-1 and analyzed in the region of 880-1190 cm-1 (ν6 bending fundamental centered at ν0 = 1018.

High resolution spectroscopy of asymmetric top molecules in nonsinglet electronic states: the ν fundamental of chlorine dioxide (OClO) free radical in the XB electronic ground state.

Highly resolved spectra of the OClO isotopologue of chlorine dioxide were recorded with a Bruker IFS 125HR Fourier transform infrared spectrometer in the region of the ν band. The analysis was made in the frame of the spin-rotational effective Hamiltonian (in A-reduction and I-representation) taking into account spin-rotational coupling operators up to the sixth order and the corresponding reduction of the Hamiltonian. The mathematical description of the ro-vibrational spectra was implemented to the specially created computer program ROVDES.