Search results for "local mode model"
showing 3 items of 3 documents
"Expanded" local mode approach and isotopic effect in polyatomic molecules
2014
In this thesis, on the base of the "expanded", local mode approach and general isotopic substitution theory we obtain sets of simple analytical relations between spectroscopic parameters (harmonic frequencies, anharmonic coefficients, ro-vibrational parameters, different kinds of Fermi and Coriolis-type interaction parameters) of the CH2D2, CH3D and CHD3 molecules. All of them are expressed as simple functions of spectroscopic parameters of the mother CH4 molecule. Test calculations with the isotopic relations show that even without including prior informations about the isotopic species, numerical results of calculations are in a good agreement both with experimental data and results of ab…
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…
On the local mode behaviour of the XH2/XD2 and XD/XH fragments with respect to the deuterated species of the near local mode XH3(C3v ) molecule
2009
International audience; Effect of isotopic substitution in the near local mode, XH3(C3v), molecules is considered. On that basis it is shown that the spectroscopic properties of deuterated and/or di-deuterated isotopic species of the XH3(C3v) molecule with the value of interbond angle close to π/2 are analogous to the spectroscopic properties of its separate fragments: of a three-atomic local mode 'molecule' XH2/XD2 and of a diatomic XD/XH 'molecule'. The phosphine molecule is considered as an illustration.