On the basis of the crystal-field theory the zero-field splitting and g-values of the ,A, ground state for d* impurity ions in a trigonally distorted octahedral field are calculated. Using perturbation theory the analytical expressions connecting the spin-Hamiltonian parameters with the crystalfield parameters are obtained. It is shown that experimental data for Cu3+ in A1,0, and Ni2+ in Also,, a-LiIO,, LiNbO, can be explained taking into account the influence of all the excited levels on the ground state. Ha OCHOBe TeOpHH KpLICTaJIJIHYeCKOrO IlOJIR IIpOBeneH paCq&T PaCIUeIIJIeHHH B HyJIeBOM nOJIe COCTORHHII ,A, HJIR IIpHMeCHbIX ds HOHOB B OKTa3ZPH-IIeCKOM IlOJIe C TpHrOHaJlLHbIM HCKalfCeHHeM. MeTonoM TeOpHM BO3M~~eHH~ IIOJIyZIeHbI aHaJILITHYeCKHe BbIPaHEeHHR, CBII3bIBaIoIUHe IlapaMeTpbI CllHH-TaMHJIbTOHHaHa C IIapa-MeTpaMH IEPHCTaJIIJILIYeCKOTO IIOJIR. nOKa3aH0, ZIT0 3KCIIepEiMeHTaJIbHble AaHHbIe nJIFJ 6Y%J&HHbIX ypOBHefii, B3aHMOAe%CTBYIoIUHX C OCHOBHbIM COCTORHHeM. g-@aKTOPOB OCHOBHOFO cu3+ B A1,0, H Ni2+ B A]@,, a-LiIo, H LiNbO, MoHHO 06'6RcHk1~L npn yYeTe BceX B03-

Optical and E P R spectra of LiNbO, single crystal doped with copper ions are measured in the range of 200 to 6000 nm and in the X-band, respectively. In the temperature range 60 to 200 K a transition is observed from the low-temperature E P R spectra with C, symmetry (gz = 2.403, gn, = 2.121, g, = 2.095 and x^c, = 51") to the high-temperature spectrum with Csv symmetry (g;l = 2.22, g ; = 2.17 and x 11 C,) whose parameters are given by the average of the corresponding parameters of the low-temperature spectra. E P R spectra of LiNbO,: Cu2+ are interpreted taking account of the static Jahn-Teller effect in trigonal field and formation of non-equivalent minima on the adiabatic potential surface. I n case of the static Jahn-Teller effect in trigonal field formulas for the g-factors of d9 ions are derived theoretically. A new model of Cu2+ substitution in LiNbO,, i.e. formation of a CUET-VL~ complex, is suggested. In optical spectra a n absorption band a t 5000 cm-' is detected due to Jahn-Teller splitting of the zEtr ground state. The Jahn-Teller stabilization energy EJT = 1250 cm-l and crystal field parameters 1ODq = 8200 cm-l, w = -1200 cm-l, and w' = 600 cm-l are determined. Tennepa. HpennomeHa HoBaH Monenb a a~e w e~~~ Cu2+ B LiNbO, -06pa30BaHIIe IFOMnJIeKcoB CUiT-VLi. B cneIcTpax OnTLZYecKoro nornoueHHR 06HapyXeHa nonoca Ha TxacToTe 5000 cm-l 06yCfiOBneHHaR FIT pacwennemeM OcHoBHoro YPOBHR 2Eg. Onpeaenemi BH~PTIIFI FIT c~a611n113aq~~ EJT = 1250 cm-l A napaiweTpb1 KpncTannwxecKoro nonrl: 10Dq = 8200 cm-l, TJ = -1200 cm-l, w' = 600 cm-l.

No abstract

Single crystals of yttrium aluminium garnet doped with zirconium ions (Y,AI,O,,: Zr, YAG: Zr) are grown from the melt and their optical and ESR absorption spectraare investigated. It is established that the color centers and paramagnetic centers have an identical nature being caused by Zr3f ions in dodechahedrical sites of the garnet lattice. The experimental results are interpreted in the approximation of crystal field and molecular orbital theories.BbIpaQeHbI E13 PaCIIJIaBa MOHOKpIICTaJIJIbI IITTpII&aJIIoMIIHIIeBOrO rpaHaTa, aHTE1BtlpOBaH-HbIe IlUpKOHIIeM (Y,A1,Ol2: Zr, HAr: Zr) II HCCJIeAOBaHbI IIX CIIertTpbI OIITII4eCECOI' O ITOJII'O-~eIIUFI II 3nP. YCTaHOBJIeHO, YTO UeHTPbI OKpaCKII E1 IIapaMaI'HItTHbIe UeHTPbI EIMeIoT MHeHTIIrIHYH) IIpIIpOAy E1 06yCJIOBJIeHbI HOHaMH wf, HaXOL(HK(IIMIIC5i B AOL(eHa3ApE1-geCKIlX y3JIaX PeILIeTHII HAr. 3KCIIepMMeHTaJIbHbIe pe3yJIbTaTbI E1HTepIIpeTHpOBaHbI B I I~H~J I~X K~H H E~ TeOpHfi Kp~cTaJI~E1YeCKOrO IIOJIII E1 MOJIeKYJIHpHbIX op6~1~aneii.

In single crystal as well as in polycrystallic samples of lead phthalocyanine of monoclinic and triclinic modification ESR signals are observed and their nature investigated. Structural change from monoclinic to triclinie modification of PbPc at 300 °C is observed. Optical absorption spectra within 200 to 1100 nm and 400 to 5000 cm−1 ranges are obtained. In μ‐PbPc thin films an anomalously wide and intense band due to intramolecular charge transfer is observed. IR reflection spectra of μ‐PbPc within the 400 to 5000 cm−1 range are registered, the plasma edge and a group of lines associated with symmetrical intermolecular vibration are found. Computation of reflection spectra by using Kramers‐Kronig relation is carried out. The frequency dependences of the real and imaginary parts of dielectric constant are computed. With use of the Drude‐Lorentz model the plasma vibrational parameters are determined.