|
1 Introduction
|
|
|
2 Two-photon transitions of the
 s and
d-states
|
|
|
3 Two-photon emission spectra
|
|
|
4 Total two-photon decay rates
|
|
|
5 Astrophysical application
|
|
|
6 Conclusions
|
|
|
Appendix A: Radial integrals
|
|
|
References
|
|
|
Online Material
|
|
|
Appendix B: Non-linear fitting functions non-resonant emission spectra
|
