http://arxiv.org/abs/1806.00542
The formation of the luminescent subordinate HeI lines by the absorption of radiation from a source in lines of main HeI series in the expanding Universe is considered. It is suggested that at some instant of time, corresponding to the redshift $z_{0}$, a burst of radiation occurs in the continuum. This radiation is partially absorbed at different $z <z_{0}$ in the lines of the main HeI series (different pumping channels) and then partially converted into radiation in subordinate lines. If $ \nu_{ij} $ is the laboratory frequency of the transition of some subordinate line originating at some $z$, then in the present time its frequency will be $ \nu=\nu_{ij}/(1+z) $. For different $z$ (and, consequently, for different $ \nu $), the radiation escape for the subordinate lines of para- and orthohelium is calculated, i.e. the number of photons emitted in the subordinate line, per one initial excited atom. Different pumping channels are considered. It is shown that the same luminescent lines can be both emission and absorption ones, depending on the initial excitation. The importance of accounting for forbidden transitions is discussed.
V. Dubrovich and T. Zalialiutdinov
Tue, 5 Jun 18
14/68
Comments: N/A