Proton collisional excitation in the lowestlying ^{3}P terms of ions in the Be and Mg isoelectronic sequences.
Abstract
Proton collisional excitation cross sections and rate constants are presented for transitions between the 3P(J) finestructure levels of the lowestlying sp configurations in a number of astrophysically important ions belonging to the Be and Mg isoelectronic sequences. The calculations were made by direct integration of the Schroedinger equation resulting from semiclassical Coulomb excitation theory. The cross sections and rate constants for the 3P(J) transitions in the lowestlying P(2) configurations are expected to be similar to those for the corresponding sp configuration transitions, and this is illustrated for C III. For the hightemperature ion Ca XVII alpha particle excitation is shown to be unimportant for situations involving ordinary values of the He/H abundance ratio. A simple, but apparently accurate method for determining certain radial integrals for lowlying excited configurations is proposed.
 Publication:

The Astrophysical Journal
 Pub Date:
 September 1979
 DOI:
 10.1086/157322
 Bibcode:
 1979ApJ...232..636L
 Keywords:

 Atomic Excitations;
 Ionic Collisions;
 Isoelectronic Sequence;
 Proton Impact;
 Alpha Particles;
 Beryllium;
 Magnesium;
 Scattering Cross Sections;
 Transition Probabilities;
 Astrophysics;
 Transition Probabilities