The ratio of intensities of inverse hydrogenlike series (IHS) luminesc
ence bands which are due to two-electron transitions in an excitonic m
olecule (EM) have been calculated. The rates of two-photon and two-ele
ctron spontaneous transitions in the excitonic molecule have been esti
mated. Their ratio has been obtained as 0.13. The correlation between
theoretical estimations and experimental results obtained from the lum
inescence spectra of beta - ZnP2 crystals has been analyzed. Copyright
(C) 1996 Published by Elsevier Science Ltd