			15min:

STARK EFFECT USING TENSORIAL FORMALISM IN THE D_2h GROUP: APPLICATION TO THE C₂H₄ MOLECULE.

W. RABALLAND, M. ROTGER, V. BOUDON, M. LOETE, Laboratoire de Physique de l'Université de Bourgogne, CNRS UMR 5027, 9, Avenue Alain Savary, BP 47870, F-21078 Dijon Cedex, France.

A tensorial formalism adapted to the case of X₂Y₄ asymmetric molecules with D_2h symmetry has been developed in the same way as in the previous works on XY₄ (T_d) and XY₆ (O_h) spherical tops, XY₅Z (C_4v) symmetric tops^, or XY₂Z₂ (C_2v) asymmetric tops. We have then constructed a Stark Hamiltonian using the same principle. This model allows the calculation of Stark shifts and splittings in the spectra of D_2h molecules. Preliminary predictions will be shown for some rovibrational bands of the C₂H₄ molecule.