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The characteristics of photocatalytic systems based on nanostructural semiconductors, characterized by quantum size effects, are discussed. An analysis is made of the consequences of exciton quantum confinement in the volume that are significant for photocatalysis and, in particular, the increase in the energy of photogenerated charges with decrease in the particle size, the photoinduced polarization processes, and also the simultaneous display of these effects. Possible ways of further increasing the effectiveness of systems based on nanostructural semiconductors are examined.

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The appearance of quantum size effects in ultradisperse semiconductors, their quantitative analysis, and their effect on the absorption of light and on the photophysical (vibrational relaxation of photogenerated "hot" charge carriers, band-band and "defect" luminescence) and certain primary photochemical processes (the accumulation of excess negative charge by the semiconductor nanoparticles, interphase electron transfer, etc.) are discussed.

Data on investigations of recent years on the creation of semiconductor photocatalytic systems for the production of hydrogen from water and aqueous solutions of electron-donating substrates are reviewed. Physicochemical approaches to extending the range of spectral sensitivity of the semiconductors (the use of sensitizers, semiconducting heterostructures, doping with metals and metalloids) are examined. Possible ways of improving the photocatalytic systems for the production of hydrogen with metal-sulfide and other types of semiconductors are analyzed. A general description of the advances and planned developments in the creation of photocatalytic converters of solar energy is given.

Notes about equivalence between the Sine -Gordon theory (free fermion point) and the free fermion theory. Abstract. The space of local integrals of motion for the Sine-Gordon theory (the free fermion point) and the theory of free fermions in the light cone coordinates is investigated. Some important differences between the spaces of local integrals of motion of these theories are obtaned. The equivalence is broken on the level of the integrals of motion between bosonic and fermionic theories (in the free fermion point). The integrals of motion are constructed without Quantum Inverse Scattering Method (QISM) and the additional quantum integrals of motion are obtained.So the QISM is not absolutely complete.

Existing data on photochemical and photocatalytic approaches to the formation of semiconducting nanoparticles and also binary semiconducting nanostructures and nanocomposites of semiconductors with metals and polymers are reviewed. The nature of the effect of irradiation on the synthesis and properties of the obtained nanostructures and the possibility of photocatalytic control of the structural and spectral parameters of nanostructural semiconducting systems are examined.The accumulation of data on the properties of semiconducting (SC) nanomaterials, which has occurred particularly rapidly in the last 7-10 years, has opened up ever more alluring prospects for their application as light-sensitive and light-emitting components in nanophotonics [1-3], nanophotocatalysis [2,[4][5][6][7], biosensorics [8][9][10][11], and other important fields. The possibility of practical utilization is an important factor that has stimulated the search for and study of the processes involved in the formation of nanomaterials. On this account an enormous number of publications have now accumulated on the improvement of existing and development of new methods for the synthesis of semiconducting nanoparticles and nanostructures (e.g., see the reviews [6, 12-15]). A special position among them is occupied by methods based on photochemical transformations conducted either for the purpose of synthesis and directing it along a desired path or for improving the characteristics of nanostructures produced by other methods.Photochemical methods of synthesis have proved more effective than the production of nanomaterials by traditional synthetic approaches, and in a number of cases only they make it possible to achieve the assigned aim. For this reason the synthesis of semiconducting nanostructures and their modification under the conditions of photoirradiation are constantly attracting the attention of investigators, and the number of publications devoted to these questions is constantly increasing. We note, however, that they nevertheless remain disjointed.In view of the foregoing an attempt is made in the present article to organize existing data, to identify the most important directions for research and development, and thus to assess the current state of development of photochemical approaches to the formation of semiconducting nanostructures. Analysis of data on the photochemical formation and post-synthesis photochemical treatment of semiconducting nanostructures and multicomponent nanocomposites, including the nanoparticles of metals and polymers in addition to semiconductors, showed that in spite of the variety and diversity of the proposed approaches all the papers can be ascribed to only three courses: synthesis, synthesis control, and changing the characteristics of the semiconducting nanostructures. For this reason in this review photochemical approaches to the synthesis of nanoparticles of metal chalcogenides, binary semiconducting nanostructures, and nanocomposites consisting of semiconducting and conducting polymers are examin...