The possible interstellar anion CH₂CN⁻: spectroscopic constants, vibrational frequencies, and other considerations

Abstract

The A B-1(1) <- (X) over tilde (1)A' excitation into the dipole-bound state of the cyanomethyl anion (CH2CN-) has been hypothesized as the carrier for one diffuse interstellar band. However, this particular molecular system has not been detected in the interstellar medium even though the related cyanomethyl radical and the isoelectronic ketenimine molecule have been found. In this study, we are employing the use of proven quartic force fields and second-order vibrational perturbation theory to compute accurate spectroscopic constants and fundamental vibrational frequencies for (X) over tilde (1)A' CH2CN- in order to assist in laboratory studies and astronomical observations.