Theoretical study of Ca+-X and Y-Ca+-X complexes important in the chemistry of ionospheric calcium (X, Y = H2O, CO2, N2, O2, and O).
Optimized geometries and vibrational frequencies are calculated for Ca(+)-X and Y-Ca(+)-X complexes (X, Y = H2O, N2, CO2, O2, and O), required for understanding the chemistry of calcium in the upper atmosphere. Both MP2 and B3LYP optimizations were performed employing 6-311+G(2d,p) basis sets. In some cases a number of different orientations had to be investigated in order to determine the one of lowest energy, and in cases involving O and O2, different spin states also had to be considered. In order to establish accurate energetics, RCCSD(T) single-point energy calculations were also employed, using aug-cc-pVQZ basis sets. Accurate dissociation energies for the Ca(+)-X and X-Ca(+)-Y species are derived and discussed. Comparison with available experimental results is made where possible.
Plowright
Richard J
RJ
School of Chemistry, University of Nottingham, University Park, Nottingham, UK.
Wright
Timothy G
TG
Plane
John M C
JM