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STARK SPECTRUM SIMULATION OF X₂Y₄ ASYMMETRIC MOLECULES: APPLICATION TO ETHYLENE IN A MFI-TYPE HOST ZEOLITE.

M. SANZHAROV, V. BOUDON, M. LOËTE, N. ZVEREVA-LOËTE, A. BALLANDRAS, G. WEBER, Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS-Université de Bourgogne, 9 avenue Alain Savary, B.P. 47870, F-21078 Dijon Cedex, France; M. ROTGER, Groupe de Spectrométrie Moléculaire et Atmosphérique (GSMA), CNRS UMR 6089, Moulin de la Housse, BP 1039, Cases 16-17, F-51687 Reims Cedex 2, France.

We present the D_2hTDS-ST (D_2h-STARK Top Data System) program suite developed to simulate Stark spectra of any IR active rovibrational polyad of X₂Y₄ (D_2h) asymmetric-top molecules. It is based on the D_2hTDS package, released for studying any rovibrational band or polyad in the abscence of an electric field ^,. The D_2hTDS-ST suite consists in a series of FORTRAN programs called by a script. For calculation of Stark spectra we obtained the expressions of the dipole moment and polarizability operators of X₂Y₄ molecules, using a tensorial formalism analogous to the one developed for tetrahedral and octahedral molecules . The developed program suite was used to estimate an effective average field in a cavity of a MFI-type host zeolite by comparison, with vibrational absorption spectra of ethylene in MFI-zeolite that have been recorded.