The paper reports on a scanning tunneling microscopy ͑STM͒ study and computer simulation with an N-body interatomic interaction potential of a graphite monolayer ͑i.e., graphene͒ on the Ni͑111͒, ͑110͒, ͑755͒, and ͑771͒ single-crystal surfaces. Unlike the case of graphene on Ni͑111͒, which forms a solid single-crystal coating with ͑1 ϫ 1͒ structure, graphene on the Ni͑110͒ surface forms a complex crystal structure distorted substantially by interaction with the substrate. Calculations of the graphene/Ni͑110͒ system have revealed that the strong chemical interaction of carbon with nickel gives rise to a noticeable curving of the graphene layer on a scale of a few angstroms. The model thus derived has permitted proper interpretation of the experimental data obtained by STM, as well as prediction of the main result of studies of graphene formed on faceted surfaces, which have revealed the ability of graphene to coat geometrically nonuniform surfaces in the form of a curved continuous film.

The possibilities of the quasimolecular "large unit cell" approach in the theory of deep energy levels in imperfect solids are discussed and some general principles of its realization are formulated. The success of this approach is illustrated by the application to the defect level problem in graphitic boron nitride (vacancies and impurity carbon atoms at boron and nitrogen lattice sites are considered). The results obtained are compared with available experimental data, and possible defect models are discussed. 0 6 c y x~~a r o~c a B03MOmHOCTH MeTOAa KBa3HMOJIeKyJIHpHOa paClUHpeHHOfi RsefiKH B TeOpIIH m y 6 o~~x JIOKaJIbHbIX YpOBHei B KpMCTaJIJIaX C jTe@eKTaMH II @OpMyJIll-MOxFHOCTefi MeTOAa paCCsIITaHb1 3JIeKTpOHHbIe COCTOHHHR Ae@eHTOB B reHCarOHaJIb-HOM HHTpHAe 6opa (BaKaHCHg H IIpMMeCHbIX aTOMOB YrJIepOna B y3JlaX 6opa I% a30Ta). rIOJIyYeHHbIe pe3yJIbTaTbI CpaBHHBaIOTCR C HMeIO4IIMllCR 3HCIIepMMeHTaJIb-HbIMII AaHHEJMH, 0 6 c y r n~a r o~c~ B03MOWHbIe MOAeJIH Ae@eKTOB.~Y I~T C R HeHoTopbie o64ae IIPHHUHIIEJ ero p e a n~a a~u a .

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