After a careful discussion of the characteristic features of the foregoing theories of an exciton in ionic crystal, a new approach to the exciton problem has been proposed, in which the one electron orbital is shown to yield already some of the characteristic properties of an exciton, an α-exciton (an exciton localized in the immediate vicinity of a negative ion vacancy) and an X-ray exciton in comparison with the experiments performed so far. In view of the present one electron orbital yielding a satisfactory zero-th order description of an exciton, a general formulation of a moving exciton based on the present one electron orbital is developed in connection with the alkali halides and an approximate estimate of a singlet exciton peak in KCl has been carried out, getting agreement with the experiment as far as approximate evaluation of the various quantities involved is permitted. A brief discussion of the effect of spin-orbit coupling on exciton multiplet has been made and a possible interpretation is presented on the splitting into doublet of the exciton peaks in KCl and NaCl below 150°K as recently observed in the relfection method of measurement by Hartman, Nelson and Siegfried. Finally, the comparison of Slater and Shockley's theory of an exciton with the present theory is discussed in some detail and the latter is concluded to be more suitable for a small size exciton.

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one electron orbital shockleys theory spinorbit coupling method xray foregoing theories exciton multiplet doublet slater

Toshinosuke Muto Sei'ichi Oyama Hiroshi Okuno,.Electronic Structure of the Exciton in Ionic Crystal: Further Discussion of a Localized Exciton (Zero-th Order Description) and General Formulation of a Moving Exciton in Alkali Halides. 20 (6),804-821.

Toshinosuke Muto Sei'ichi Oyama Hiroshi Okuno,"Electronic Structure of the Exciton in Ionic Crystal: Further Discussion of a Localized Exciton (Zero-th Order Description) and General Formulation of a Moving Exciton in Alkali Halides" 20

Toshinosuke Muto Sei'ichi Oyama Hiroshi Okuno,"Electronic Structure of the Exciton in Ionic Crystal: Further Discussion of a Localized Exciton (Zero-th Order Description) and General Formulation of a Moving Exciton in Alkali Halides"