A magnetic-resonant modulation of the photoconductivity of polycrystalline samples of CT complex anthracene-TCNR is observed. The modulation is due to microwave induced transitions between Zeeman sublevel8 of the excited triplet CT state. The magnetic resonance spectrum of the CT triplet state is registered, the lifetime of the latter is estimated to be about 10-8 s. Switching-on the resonant microwave field decreases the photoconductivity. The nonresonant effect of the permanent magnetic field on photocurrent and fluorescence of anthracene-TCNB crystals is investigated. A scheme is given representing the processes of the electronic excitation energy conversion in the anthracene-TCNB CT complex.Ha6nmnanacb Mal'HHTHO-Pe30HaHCHaH MOHyJIRUHH @OTOIIpOBOn&iMOCTH IIonaKpHcTaJI-JIHgeCHHX o6pa3uo~ KOMIIJleKCa C IIepeHOCOM 3apRna aHTpaUeH-TeTpaUElaH6eH3OJI, CBII3aHHaR C OCy4eCTBJIeHHeM CBY-noneM pe30HaHCHbIX IIepeXOAOB MeXny 3eeMaHOB-CKHMH IIOEYPOBHHMEI BO36yXneHHOrO TpHIIJIeTHOI'O COCTOIIHHII C IIepeHOCOM 3apHna. X H a H H OKOJIO8 . BHnmeHue pe3OHaHCHOfi CBY-MOIIJHOCTH YMeHLIIIaJIO BeJIHWlHy @OTOIIPOBOAHMOCTH. ~CCJleAOBaHO TaKXe Hepe3OHaHCHOe BJIHRHHe CTaUkiOHaPHOrO MaI'HHTHOI'O IIOJIR Ha @OToIIpOBOLWi MOCTL H @JIyOpeCUeHUEIIO KpHCTaJIJIOB aHTpaUeH-TeTpaUHaIIH6eH3OJl. npe&llOXeHa CXeMa IIpOUeCCOB C YWl CTHeM 3JIeKTpOHHO-BO36y)K~eH-HbIX H HOHH3HPOBaHHbIX COCTOIIHElfi B HCCJIeEOBaHHblX KpHCTaJlJIaX. 3 a p e r~c~p~p o s a~ cnemp MarHmHoro p e 3 o~a~c a 3~0 r o cocTonnm, n~em4ero sperm

An investigation is made of the mechanism of photoconductivity of needle-shaped single crystals of a weak charge transfer complex formed by anthracene and dimethylpyromellitimide. In the crystals of the charge transfer (CT) complex, the annihilation of triplet excitons is shown t o generate charge carriers. The contribution of this process to the photoconductivity is evaluated. The photoconductivity of the CT-complexes is found to exhibit a sensitivity toward weak external magnetic fields as a result of the variations in the rate constants of triplet-triplet annihilation and intersystem crossing in excited states of the CT-complex. A scheme is proposed to represent the processes involving excited and ionized states in the crystals of the anthracene-dimethylpyromellitimide CT-complex. I) Moscow 117334, USSR.

The Magnetic Field Effect E. L. FRANKEVICH, M. M. TRIBEL, and I. A. SOROLTRThe mechanism of carrier generation in sublimated rubrene films in the course of their oxidation is investigated. The technique of the simultaneous measurement of photoconductivity and fluorescence of the samples and their variation in magnetic fields up to 3 kOe is employed. The excited states whose deactivation leads to both, fluorescence and carrier generation in unoxidized films are found to be rubrene singlet excited molecules 'MI and in films exposed to air. excited complexes of 'RZ, with 0, molecules and with transannular rubrene peroxide molecules RIO,. The probability of carrier generation in the interaction of 'Nil with 0, is higher than with MO,. The existence is shown of a n efficient channel of generation of triplet rubrene excitons, associated with the deactivation of excited triplet complexes of rubrene with MO,. The influence is investigated of variations in the crystalline structure of films on the behaviour of photoconductivity. Hax py6pesa B npouecce IIX oKmneHm. lIpuMeHeHa nieTonma OAHoBpeMeHHoro ucra~epe~m @OTOII~OBOJU~MOCTB B QmyopecueHuna o6pa3qo~, a TaKme ux ume-I/ICCJIenOBaH MeXaH113M reHepaUHl1 HOCHTenefi TOKa D CY6JlHMApOBaHHbIX nJIeH-HeHAfi B MarHElTHbIX IIOJIFIX HanPFIXeHHOCTbW A 0 3 koe. nOKa3aH0, 9 T O B036ym-HeHHbIMA COCTOFIHBHMM, Ae3aKTHBaUMFI KoToPbIX IIPRBOHRT KaK K @JIyOpeCqeHqAA, TPK EI H reHepaUHI4 HOCATeJIefi TOKB, B HeOKHCJleHHbIX IIJIeHHaX XBJIFIWTCII CAH-rjIeTHbIe B036YWAeHHble MoJIeKyJlbI py6peHa 'hfl, a B IIJIeHKaX, MMeBIlIAX HOHTaKT C B03AYXOM, -BO36ymneHHble KOMnJIeKCbI, 06pa30BaHHbIe '&Il C MOJleHyJlaMH BepOFITHOCTb 06pa30BaHHX HOCHTeJIefi TOKa IIpH B3aAMOnefiCTB&4H 'MI C 0, BbILLIe, 9eM C MO,. nOKa3aHO CyWCCTBOBaHMe B@@eKTUBHOTO HaHaJIa reHepauME3 TpEinJleT-HbIX BKCHTOHOB p y 6 p e~a , CBH3PHHOTO C ne3aHTHBaUElefh TpHnJIeTHbIX B036yXneH-HblX HOMnJIeKCOB py6peaa C MOJleHYJIaMA &PO,. MCCJlenOBaHo TaK)iie BJIMflHHe U3MeHeHMfi KpHCTaJlJIHqeCKOfi CTPYHTYPbI nJIeHOK Ha IIOBeneHEle @OTonpOBOAK-MOCTI?. K A C J I O~O~~ 0,, a TaKme c MoneKynaMM TpaHcaHHynXpHom nepeKMcM p y 6 p e~a MO,.

An investigation is made of the line shape of the low field resonances observed in the dependence of the fluorescence of a single A-TCNB CT crystal on the external magnetic field. It is shown that the resonance is caused by avoided crossing of magnetic sublevels of it single T-exciton arising when the direction of the field is close to the axis of the fine interaction tensor. An analytic expression for the resonance line shape is obtained. The spin-lattice relaxation rate of T-excitons, tions, (ol = (5 + 2) x 107 5-1, are determined. 3~c n e p a~e a~a n b~o HccneHoBaHa #opMa JIHHMH H H~K O I I O J I~B O~O p e 3 o~a~c a B BBBHCH-t-l --(1.0 0.3) x lo7 s-l as well as the rate of jumps between the planes of fast exciton migra-MOCTM @IIoOpeCUeHUHll MOHOKpHCTaJIJIa H n 3 A-TU6 OT IIOCTORHHOI'O BHeIUHerO MarH&iTHOI' O IIOJIR. Pe3J' JIbTaTbI HHTepIIpeTHpOBaHhI B IIpeJUIOJIO?KeHHH, YTO @JIIoOpeC-KBa3HIIePeCeYeHHeM MarHHTHbIX IIOAYpOBHefi T-3IECHTOHOB IIpH HaIIpaBJleHMH I I 0 3 R 6JIH3KOM Ic OCH TeH3Opa TOHKOrO B3aHMOAefiCTBIU€. B PaMKaX pawee IIpe&JlOWeHHOfi UeiIuHH 06yCJIOBJIeHa TT-aHHmrHnRuet. n o~a 3 a~0 , YTO 3TOT pe30HaHc 06yCJIOBJIeH MoAenH TT-aHHHrmnHqm nonyseHa aHanklTmecHaR #opMyna ~IJIR (POPM~I JIHHHH p e a o~a~c a . OnpeaeneHa crcopomb CPP T-3ISCHTOHOB: t -l = (1.0 & 0,3) x lo7 s-l H CKOpOCT b IIpbImHOB Meway IIJIOCKOCTRMH 6bIcTpofi MHrpaUHH 3KCHTOHOB O1 = (5 f 2) X x 107 8-1.

Magnetic Spin Phenomena in the Chlorophyll PhotoconductivityBY E. L. FRANKEVICH (a), M. M. TRIBEL (a), I. A. SOKOLIK (a), L. I. KOLESNIKOVA (a), and Yu. M. STOLOVITSEII (b)Modulation of the chlorophyll "a" (Chl) photoconductivity by an external magnetic field due t o variations of the rate of non-equilibrium spin processes under the action of a magnetic field is observed. These processes are charge carrier generation and charge detrapping by Chl triplet. Application of a magnetic field causes two types of variations of the photoconductivity of Chl films in vacuum: (i) instantaneous (t < 1 s) increase of the photoconductivity and (ii) slow decrease with time constant t = 10 to 100 8. The influence of temperature and intensity of the exciting light on the magnetic field effects is investigated. A scheme of energy transformation processes in Chl involving electron-excited and ionized states is presented. The presence of oxygen leads to an increase of the photoconductivity of Chl, as compared with the vacuum values, and to a change in the dependence of photoconductivity on magnetic field. These changes are shown to occur due to the appearance of new acceptor centres arising from unstable products of Chl photooxidation. Ha6~11onanacb MOAJ'JIFIUHR BHeUIHHM MarHHTHbIM EOJIeM BeJM9kIHbI @OTOIlpOBOnHMOCTH XJIOpO@HJIJIa "a", 06yCJIOBJIeHHaR M3MeHeHHeM B MarHHTHOM IIOJIe CKOpOCTefi HepaBHOBeC-HbIX CIlHHOBblX IIpOUeCCOB : 0 6 p a 3 0 B a H H R HOCIXTenefi T O K a H OCBO6O)KAeHHH 3 a X B a q e H H b I X JIOByUIKaMH 3 a p H n O B . YCTaHOBJleHO, YTO H a J r O W e H H e MarHHTHOrO XlOJIH BbI3bIBaeT n B a BHAa H3MeHeHHfi @OTOllpOBO~HMOCTH BaKYYMHPOBaHHbIX IIJIeHOK XJIOpO@HJIJIa C p a 3 J I H q -HOfi BpeMeHHOfi 3aBHCIXMOCTbIO : 6e3bIHepUHOHHOe (t < 1 8 ) YBeJIHqeHHe