Predicted rovibronic spectra of CH2+ and CD2+

We present simulations of the A2B1←X2A1 electronic band systems of CH2+ and CD2+ in absorption at 200 K. For each isotopomer we calculate the spectrum over the range from 5000 to 18 000 cm−1 for the purpose of assisting the experimental search of the spectrum in a cooled hollow-cathode discharge. We make use of our previously determined ab initio potential energy surfaces, dipole moment and transition moment surfaces in a calculation that includes the Renner–Teller effect and spin–orbit coupling. To complete the picture we also present simulations of the rotation and rotation–vibration spectra of CD2+.