An MRCI investigation of the electronically excited states of difluorocarbene and its monovalent ions

Abstract

The MRCI/CBS computational protocol was employed to describe the low-lying electronic states of CF 2 in excellent agreement with experiment. Also of interest for modeling the fluorocarbon plasmas are the difluorocarbene ions, and the geometries, adiabatic excitation energies and orbital characteristics of their electronically excited states were established. Most of the transitions leading to the excited states were found to be monoelectronic and, for the dipole-allowed ones, the oscillator strengths and radiative lifetimes were predicted to aid in the spectroscopic studies.

Modeling Chemical Evolution in a Cold Molecular Plasma: Quantum Dynamics of CF2– Intermediates after Electron Attachment

“…It is shown that the system moves down to crossing the corresponding PES of the N-electron system (which has its E = 0.0 value at the R eq position shown by the vertical dotted line) at a bond distance of about 1.40 Å. It is interesting to note that earlier ab initio calculations for the stable anion of 2 B 1 symmetry 37 found that its minimum energy structure was for R eq ∼1.438 Å and close to the experimental estimate of 1.45 ( 0.02 Å . 43 A smooth extrapolation of our scattering results into the bound-state region suggests a bond length of ∼1.44 Å in good agreement with the above data.…”

“…The properties of CF 2 at the equilibrium geometry were the subject of several papers from both theoretical − and experimental − viewpoints. The geometry of its ground state was studied spectroscopically in the microwave , and infrared , regions, and structural parameters of the ground state have been derived from absorption spectroscopy .…”

“…A smooth extrapolation of our scattering results into the bound-state region suggests a bond length of ∼1.44 Å in good agreement with the above data. Furthermore, the bond angle we used was the θ eq = 104.73° while the estimates , for the stable anion are around 100°. Thus, the pure stretching “cut” of the present PES is still an approximate view that is already providing the correct result.…”