Comparison of quantum, semi-classical and classical methods in the calculation of nitrogen self-broadened linewidths

We perform dynamical calculations on two robust N2-N2 potential energy surfaces in order to intercompare pressure broadening coefficients derived from close coupling and coupled states quantum dynamical methods, the semi-classical model of Robert and Bonamy and a full classical method. The coupled states and full classical results compare well with the experimental results or with close coupling values when available. This study confirms that the classical method is a good alternative at room and high temperatures to quantum dynamical methods. The results obtained using the semi-classical method however deviate from the other sets of data at all temperatures considered here (77-2400 K).

► Self-broadening coefficients for N2 on a large scale of temperature. ► Comparison between various theoretical methods. ► Accuracy of the quantum and classical methods used with an accurate PES. ► Failing of the Robert-Bonamy method.