Issue |
Astron. Astrophys. Suppl. Ser.
Volume 128, Number 3, March II 1998
|
|
---|---|---|
Page(s) | 581 - 588 | |
DOI | https://doi.org/10.1051/aas:1998165 | |
Published online | 15 March 1998 |
Effective collision strengths for electron impact excitation of Xe III, Xe IV, Xe VI and Ba II, Ba IV
Institut für Astronomie und Astrophysik der Universität München, Scheinerstr. 1, D-81679 München, Germany
Received:
12
February
1997
Accepted:
24
July
1997
Effective electron excitation collision strengths have been calculated for
fine-structure forbidden transitions within the 5pk (, 3, 4)
ground configurations of Xe iii, Xe iv, Xe vi and the 5p5 configuration
of Ba iv. In addition calculations
have been performed for allowed and forbidden transitions within the three
lowest configurations of Ba ii. For astrophysical applications the data are
tabulated in the range
K. The applicability of the
Breit-Pauli R-matrix technique to the computation of collision strengths
for xenon and barium ions has been investigated by comparison with test
calculations using the Dirac R-matrix method. Our data will be employed
in quantitative analyses of highly excited nebular spectra,
especially of NGC 7027 where important implications for the interpretation
of collisionally excited transitions in the heavy ions are expected.
Key words: atomic data / plasmas / planetary nebulae: NGC 7027
© European Southern Observatory (ESO), 1998