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Electron paramagnetic resonance (EPR) lineshapes of nitroxide spin probes in a variety of organic supercooled liquids and glasses were analyzed within the framework of the fast librational motion model. Computer simulation confirmed that the EPR lineshape may be fitted well by the librational model. For all systems studied, a mean-squared amplitude of this motion, 〈α2〉, was found to depend linearly on temperature in the low-temperature region, which is typical of harmonic solids. The slope of the linear dependence varies from glass to glass and does not change for different nitroxides in the same glass. This slope seems to correlate with the strength of the intermolecular bonds and with a degree of the fragility of the glass. Steep rises in 〈α2〉 were observed at high temperature.

The construction of the DC-60 Heavy Ion Cyclotron for the Interdisciplinary Scientific Research Complex (ISRC) in Astana started in early 2004. The cyclotron was manufactured and tested at the Flerov Laboratory of Nuclear Reactions (FLNR) in Dubna. The main units were delivered to Astana and assembled in the ISRC building in the summer of 2006. The cyclotron was turned on in September, 2006. The first heavy ion beams in the whole A/Z and energy ranges were accelerated and extracted in December, 2006.

A new separator and mass analyzer of super heavy atoms (MASHA) has been created at the FLNR JINR Dubna to separate and measure masses of nuclei and molecules with precision better than 10−3. First experiments with the FEBIAD plasma ion source have been done and give an efficiency of ionization of up to 20% for Kr with a low flow test leak (6 particle μA). We suppose a magnetic field optimization, using the additional electrode (einzel lens type) in the extracting system, and an improving of the vacuum conditions in order to increase the ion source efficiency.

Spin-dynamics of the spin-correlated radical pair (SCRP) P(700)(+)A(1A)(-) in the photosystem I (PSI) reaction center protein have been investigated with high-frequency (HF), time-resolved EPR spectroscopy. The superior spectral resolution of HF EPR enables spin-dynamics for both the donor and acceptor radicals in the pair to be monitored independently. Decay constants of each spin were measured as a function of temperature and compared to data obtained at X-band EPR. Relaxation times, T(1), and decay rates, k(S), are the same at both X- and D-band magnetic fields. The spin-dynamics within the radical pair were determined from theoretical simulation of experimental time-resolved HF EPR spectra. At low temperatures, T60 K, the decay of the SCRP from the singlet state, k(S), is the predominant process, while at high temperatures, T130 K, the T(1) relaxation is much faster than k(S). The recombination rate k(S) was observed to decrease as the temperature is increased. These EPR spectral results are in agreement with previously reported optical measurements of P(700)(+)A(1)(-) radical pair recombination.

A high-field (D-band, 130 GHz) electron spin echo-detected spectrum of the primary electron donor triplet state, P-3, in quinone-depleted photosynthetic reaction centers from the bacterium Rhodobacter sphaeroides R26 is obtained. It shows a significant g-anisotropy, which is larger than that of the primary donor oxidized state, P+. Simulation gives the triplet g-tensor principal values of 2.0037, 2.0028, and 2.0022 (precision +/-0.0001), assuming that the g-tensor is coaxial to a zerofield splitting tensor. The P-3 spectral lineshape reveals an orientational anisotropy of the triplet quantum yield. We explain this anisotropy as arising from the difference in the main values and relative orientations between the g-tensors of P+ and I-A(-.) in the primary radical pair (the triplet state's precursor).

A “liquid He-free” superconducting electron cyclotron resonance ion Source DECRIS-SC, to be used as an injector for the compact IC-100 cyclotron, has been designed and built in cooperation between the FLNR and LHE (JINR). The main feature is that a compact refrigerator of the Gifford-McMahon type is used to cool the solenoid coils. Due to a very small cooling power at 4.2K (about 1W) our efforts were aimed at optimizing the magnetic structure and minimizing external heating of the coils. The maximum magnetic-field strengths are 3 and 2T in the injection and extraction regions, respectively. When the source had been assembled and magnetic field measured, the ion source was immediately installed at the injection line of the cyclotron. During the first tests, which were run only a few days, some problems arose due to a relatively poor efficiency of the beam transport and analyzing line. From the moment of the first reliable beam production up to now the ion source has been operating continuously for the cycl...

The secondary photoinduced radical pair state P+• QA-• in Zn-substituted and quinone-reconstituted photosynthetic reaction centers of Rhodobacter sphaeroides R26 is investigated with transient EPR spectroscopy at X- (9.3 GHz), Q- (34.7 GHz), and D-band (130.0 GHz) microwave frequencies. Novel D-band P+• QA-• electron spin-polarized spectra are presented for three different reconstituted reaction centers. The shape of the electron spin-polarized P+• QA-• EPR spectrum strongly depends on the lifetime and magnetic properties of its precursor radical pair P+• ΦA-•, whose lifetime was manipulated by replacing the native ubiquinone-10 (UQ-10) with duroquinone (DQ) or 2-ethyl anthraquinone (AQ). From spectral simulations incorporating the transfer of spin-correlation between the two radical pairs, information about the magnetic interactions and dynamics of the intermediate primary P+• ΦA-• radical pair was obtained. When the lifetime of P+• ΦA-• is longer than a few nanoseconds, the influence of the magnitude an...