Étude du spectre d'absorption du méthane 13CD4 dans la region de 1000 cm−1 analyse de la diade ν2/ν4

The Fourier transform absorption spectrum of 13CD4 methane has been recorded from 924 to 1190 cm−1. The full width half maximum (3 × 10−3 cm−1) of the lines in the experimental spectrum is close to the Doppler–Fizeau width (2.7 × 10−3 cm−1) and the accuracy of the line frequency is better than 10−4 cm−1. The reduced effective Hamiltonian is formulated in terms of irreducible tensorial operators set in the Td group. With 1147 isolated infrared lines, we have determined 10 Hamiltonian parameters for the ground state up to sixth order and 30 parameters of the 0100 and 0001 vibrational states up to the fifth order of approximation. The standard deviation obtained is 10−4 cm−1.