0000000000813898
AUTHOR
A.l. Fomchenko
showing 5 related works from this author
On the determination of the intramolecular potential energy surface of polyatomic molecules: Hydrogen sulfide and formaldehyde as an illustration
2009
International audience; We present here an approach for determining the Hamiltonian of polyatomic molecules that allows one to successfully solve the problem of potential energy surface (PES) determination via construction and diagonalization of a Hamiltonian matrix of large dimension. In the suggested approach, the Hamiltonian is very simple and can be used both for any "normal" polyatomic molecule and for any isotopic species of a molecule. Molecules with two to four equivalent X-Y bonds are considered, and for illustration of the efficiency of the suggested approach, numerical calculations are made for the three-atomic (hydrogen sulfide) and four-atomic (formaldehyde) molecules.
On the ‘expanded local mode’ approach applied to the methane molecule: isotopic substitution CH2D2←CH4
2011
On the basis of a compilation of the ‘expanded local mode’ model and the general isotopic substitution theory, sets of simple analytical relations between different spectroscopic parameters (harmonic frequencies, ωλ, anharmonic coefficients, x λμ, ro-vibrational coefficients, , different kinds of Fermi- and Coriolis-type interaction parameters) of the CH2D2 molecule are derived. All of them are expressed as simple functions of a few initial spectroscopic parameters of the mother, CH4, molecule. Test calculations with the derived isotopic relations show that, in spite of a total absence of initial information about the CH2D2 species, the numerical results of the calculations have a very good…
On the ‘expanded local mode’ approach applied to the methane molecule: isotopic substitutions CH3D ←CH4 and CHD3 ←CH4
2014
Operator perturbation theory and the symmetry properties of the axially symmetric XYZ3 (C3v) type molecules are used for the determination of the spectroscopic parameters in the form of functions of structural parameters and parameters of the intramolecular potential function. Several relations between sets of spectroscopic parameters of these molecules are obtained. The ‘expanded local mode’ model and the general isotopic substitution theory are used to estimate the relations between spectroscopic parameters of CH3D and CHD3, on one hand, and with the Td symmetric isotopic species, CH4, on the other hand. Test calculations with the isotopic relations show that even without including prior …
On the "Expanded" Local Mode Approach and Isotopic Eff ect (CH2D2/CH3D/CHD3) in the Methane Molecule.
2010
Earlier derived, [1] - [3], for the XY2 (C2v) and XY3 (C3v) molecules "expanded local mode model" is applied to the methane-type, XH4, molecules. Value of the ambiguity parameter, sin \_gamma, simple value of all transformation coefficients, l, are obtained for the CH4 molecule. It gives us possibility, on the one hand, 1). to derive simple relations between different spectroscopic parameters (harmonic frequencies, anharmonic parameters and vibrational tetrahedral coefficients, rotational-vibrational and rotational tetrahedral coefficients) of the CH4 molecule, and, on the other hand, 2). on the base of the general isotopic substitution theory (see, e:g:, [4]), to obtain very simple values …
On the 'expanded local mode' approach applied to the methane molecule: isotopic substitution CH2D2 <--- CH4
2011
International audience; On the basis of a compilation of the 'expanded local mode' model and the general isotopic substitution theory, sets of simple analytical relations between different spectroscopic parameters (harmonic frequencies, anharmonic coefficients, ro-vibrational coefficients, different kinds of Fermi- and Coriolis-type interaction parameters) of the CH2D2 molecule are derived. All of them are expressed as simple functions of a few initial spectroscopic parameters of the mother, CH4, molecule. Test calculations with the derived isotopic relations show that, in spite of a total absence of initial information about the CH2D2 species, the numerical results of the calculations have…