ELECTRON IMPACT EXCITATION CROSS SECTIONS AND RATES FROM THE GROUND STATE OF ATOMIC CALCIUM

✍ Scribed by ANDY M. SAMSON; KEITH A. BERRINGTON

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 72 KB
• Volume: 77
• Category: Article
• ISSN: 0092-640X
• DOI: 10.1006/adnd.2000.0847

✦ Synopsis

New R-matrix calculations are presented for electron excitation of atomic calcium. The target state expansion includes 22 states: 4s 2 1 S; 4snl 1,3 L, where nl is 3d, 4p, 5s, 5p, 4d and 4 f ; 3d4p 1,3 P, D, F; and 4 p 2 3 P, 1 D, 1 S terms. The calculation is in L S coupling, and configuration interaction involving 3 p subshell correlation is included. Electron impact excitation cross sections from the 4s 2 ground state to the next 10 states are tabulated for low energies, and thermally averaged effective collision strengths are tabulated over a range of electron temperatures from 1000 to 10,000 K. Comparisons are made with previous cross sections calculations for the 4s 2 -4s4 p 3 P o transition; excellent agreement is found with experimentally derived rates for 4s 2 -4s4 p 1 P o .