Use of molecular symmetry to describe pauli principle effects on the vibration-rotation spectroscopy of CO2(g)

A previous article published in this Journal (2002, 79, 117) described the vibration–rotation spectroscopy of the asymmetric stretching fundamental infrared CO2 absorbance and its use in an undergraduate laboratory. The consequence of the nuclear spin of oxygen (I = 0) on the rotational fine structure of this absorbance is to forbid alternate rotational levels, causing the observed spacing between rotation–vibration lines to be twice that expected for linear nonhomonuclear molecules such as HCl. The present article presents a systematic method for obtaining the Pauli principle rules based on the analysis of a series of symmetry operations equivalent to the exchange of identical oxygen nuclei in CO2.