Measurement of absolute line intensities in the ν5-ν4 band of 12C2H2 using SOLEIL synchrotron far infrared AILES beamline

Absolute intensities of about 120 lines of the 12C2H2 molecule are reported for the ν4-ν5 band between 65 and 192 cm-1, with an average accuracy of 5%. Vibrational transition dipole moment squared values and empirical Herman-Wallis coefficients are obtained allowing modelling the rotational dependence of the transition dipole moment squared. Special care is taken to accurately determine an apparatus function for the Bruker IFS 125-HR coupled to the synchrotron SOLEIL far infrared AILES beamline in order to minimize its effects on the line parameter retrieval.