Laser separation of isotopes

The first part of the review gives classification of optical (photochemical and photophysical) methods of isotope separation, describes the history of their elaboration and the advantages of laser radiation. Then consideration is given to the problem of isotopically selective excitation and isotope shifts in atomic and molecular spectra, limitation of selectivity and methods of its increase. The method of selective two-step atomic photoionization, general relations for this method, basic experiments (Rb, U, etc.), methods for increasing the photoionization cross-section of excited atoms and for ionization selectivity limitation are studied. The method of selective two-step molecular photodissociation and its limitations (the ''bottle neck'' effect due to rotational structure, steepness of photoabsorption limit, nonselective thermal excitation), the first experiments (NH3, BCl3) are considered, as well as the method of selective molecular photopredissociation, its limitations and advantages, the first experiments (H2CO, I2), prospects of its application to isotope separation