Line Intensity Measurements of the ν7+ν8 Band of Ethylene (12C2H4)

From the four high-resolution FTIR absorbance spectra recorded at a spectral resolution of 0.0063 cm−1, 123 line intensities belonging to the ν7+ν8 band of 12C2H4 were measured and fit. The upper v7+v8=1 state rovibrational constants up to sextic terms determined using a Watson's A-reduced Hamiltonian model in Ir representation were used to calculate the line intensities of the band. Results of the experimental fit of the line intensities agree well with those obtained by calculations