Prediction of the infrared spectrum for the neon–ethylene van der Waals complex

The van der Waals states of Ne–C2H4 up to J=10 are calculated with the ethylene molecule in both its ground and ν7 excited vibrational states. The method involves separation of the van der Waals bending motions from the stretching motions and ethylene vibrations. The infrared spectrum of the complex is predicted in the region of the ethylene ν7 vibrational mode, and the results are compared with the calculated spectrum of free ethylene. The effect of ignoring off-diagonal Coriolis terms (which mix together different K states) in the Ne–C2H4 Hamiltonian is investigated.