Geometry of the CaOCH3 radical from isotope effects in the A˜2E-X˜2A1 transition

The analysis of laser excitation spectra of the A˜2E-X˜2A1 origin band of the CaOCH3 radical reported in 2002 [J. Mol. Spectrosc. 213 (2002) 28] left some geometric parameters undetermined. Working with isotopically substituted methoxy groups, with 12C or 13C and complete D/H substitution, we have recorded the origin bands and the 401 band of the A˜-X˜ system of four isotopomers of calcium monomethoxide. The rotational constants derived from the analysis of the spectra are used in a fit to determine bond lengths and angles in the two electronic states.