Testing the mass - scaling relations in the a 3 P state of 12 C 18 O and 13 C 16 O

Electronic spectra of the aP–XR (0–0) and (1–0) bands of CO, and the (1–0) band of CO are measured by cavity ring-down spectroscopy in the 200 nm region. The experimental spectra are analyzed using the molecular constants predicted by mass-scaling relations. It is found that the mass-scaling rules for the aP state can be used to predict the transition frequencies from v = 0, J < 8 in CO to v = 1 and J < 30 rovibrational levels in both CO and CO within the experimental accuracy of 0.2 cm . 2013 Elsevier Inc. All rights reserved.