{'fraction_non_alphanumeric': 0.01557285873192436, 'fraction_numerical': 0.004449388209121246, 'mean_word_length': 4.960264900662252, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Resonance LO Phonon-Assisted Luminescence and Light and Heavy Excitons in NaI Crystals

The resonance multiphonon luminescence spectra of NaI single crystals are investigated experimentally in the temperature region of 4.2 to 65 K. A detailed investigation of the temperature dependence of peak energies and the intensities of the components of the luminescence spectrum as well as a theoretical analysis reveal an unknown component in the region of the zero-phonon line. This component is interpreted in the framework of the model of light and heavy excitons. On the basis of experimental data for NaI the energy Δ, induced by the short-range part of exchange interaction, is evaluated. Peculiarities of resonance luminescence in alkali iodides are analysed by using the theory of resonance multiphonon luminescence developed in the studies of semiconductor crystals. 
 
 
 
[Russian Text Ignored].