l-type resonances in C2H2

Abstract
A full Hamiltonian matrix coherent with a phase convention leading to e/f labellings and to positive l-doubling q parameters is constructed to describe the rovibrational energy levels in a linear polyatomic molecule with two bending vibrations. This model is used to investigate quantitatively the effect of the rotational and vibrational l resonances on level mixings and intensity features in C2H2.