ANTICROSSINGS IN THE ACETYLENE MOLECULE FOURIER TRANSFORM ANALYSIS : MEAN COUPLING, LEVEL DENSITY

Abstract
By using a home made dye laser we excite, in the U.V. range, the acetylene molecule (C₂H₂) in gas phase. Four rotationless vibrational levels have been selected to obtain anticrossing spectra up to 8 tesla. To statistically analyze this data we have developped a method based on a Fourier Transform (TF) technique and on a fitting of the resulting curves. This first analysis gives the probability law of the singlet-triplet coupling for the different excited levels. A second analysis allows to extract from the first analysis of the data the vibrational level densities ([MATH]), the products [MATH] and the mean couplings ([MATH]). Finally we will present the variation of the product [MATH] as an increasing exponential fonction of the excitation energy.