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Title: Potential energies for Ca/sub 2//sup ts+/: Cross sections for collisions of Ca/sup +/ and Rydberg Ca/sup asteriskasterisk/ with Ca

Journal Article · · Phys. Rev., A; (United States)

Ab initio self-consistent-field (SCF) and configuration interaction (CI) calculations have yielded potential energy curves for the lowest /sup 2/..sigma../sup +//sub u/ and /sup 2/..sigma../sup +//sub g/ states of Ca/sub 2//sup ts+/. The best CI calculation yields the following parameters for the /sup 2/..sigma../sup +//sub u/ state: D/sub e/ = 1.04 eV, R/sub e/ = 7.55a/sub 0/, ..omega../sub e/ = 119 cm/sup -1/, and B/sub e/ = 0.0526 cm/sup -1/. The long-range regions of the /sup 2/..sigma../sup +//sub u/ and /sup 2/..sigma../sup +//sub g/ potential curves are both characterized by a Ca dipole polarizability of 170.4a/sup 3//sub 0/, in good agreement with the experimental value of (169 +- 17) a/sup 3//sub 0/. The charge-transfer total cross sections have been calculated over the energy range E/sub cm/ = 10--10 000 eV and are well reproduced by the functional form Q/sup 1/2/(A) = 15.67 - 3.276 log/sub 10/ E/sub cm/ (eV). The elastic differential-scattering rainbow angle is predicted to be located at Etheta/sub R/ approx. = 90 eV deg. Collisional-ionization cross sections and rates were also estimated for Rydberg-atom Ca** + ground-state Ca collisions. The reaction rates are predicted to be on the order of 10/sup -10/ cm/sup 3//sec and depend linearly on the principal quantum number n of the Rydberg atom.

Research Organization:
IBM Research Laboratory, Monterey and Cottle Roads, San Jose, California 95197
OSTI ID:
6587571
Journal Information:
Phys. Rev., A; (United States), Vol. 18:6
Country of Publication:
United States
Language:
English