Ferro-electric phase transition in a polar liquid and the nature of \lambda-transition in supercooled water

We develop a series of approximations to calculate free energy of a polar liquid. We show that long range nature of dipole interactions between the molecules leads to para-electric state instability at low temperatures and to a second-order phase transition. We establish the transition temperature, T_{c}, both within mean field and ring diagrams approximation and show that the ferro-electric transition may play an important role explaining a number of peculiar properties of supercooled water, such as weak singularity of dielectric constant as well as to a large extent anomalous density behavior. Finally we discuss the role of fluctuations, shorter range forces and establish connections with phenomenological models of polar liquids.Comment: 5 pages, 1 eps figure, density anomaly at T=4C analysis adde

The explanation of unexpected temperature dependence of the muon catalysis in solid deuterium

It is shown that due to the smallness of the inelastic cross-section of the $d\mu$-atoms scattering in the crystal lattice at sufficiently low temperatures the $dd\mu$-mesomolecules formation from the upper state of the hyperfine structure $d\mu (F=3/2)$ starts earlier than the mesoatoms thermolization. It explains an approximate constancy of the $dd\mu$-mesomolecule formation rate in solid deuterium.Comment: 6 pages, 2 jpeg-figure

Determination of platinum-group elements in rocks by ICP-MS with external calibration after cation exchange separation of matrix elements by KU-2-8 resin

The analytical technique to determine platinum-group elements (PGEs) Ru, Rh, Pd, Ir, Pt and Re in the geological samples within 0.1 ng/g – 10 μg/g range and Os on ng/g level in the ultramafic rocks by inductively coupled plasma mass-spectrometry with external calibration and without chemical removal of main interferences of Zr and Hf was proposed. The samples were prepared after their burning by acid decomposition in the open vessels, melting the insoluble residue with NH4 F and with a subsequent cation exchange separation of PGEs from matrix elements by KU-2-8 resin (Russia). The measurements have been carried out using the high resolution mass-spectrometer Element 2 (Germany). The accuracy of the technique on μg/g level has been verified with reference materials: pyrrhotite ore RP-1 (Russia) and sulfide copper-nickel ore Zh-3 (Russia). In addition, the accuracy of the trace level (ng/g) has been verified by comparison of the results obtained in this study with those reported in the literature for international sample of comparison OPY-1, developed by the International Association of Geoanalysts (IAG). The procedural blanks are 0.000n ng/ml for Os, 0.00n ng/ml for Ru, Rh, Re, Ir and 0.0n ng/ml for Pt and Pd. The detection limits were estimated by taking into account the blanks and their standard deviations (sample mass 1 g, volume 50 ml) and were 0.02 ng/g for Os, 0.07 ng/g for Re, 0.09 ng/g for Rh and Ir, 0.13 ng/g for Ru, 1.0 ng/g for Pt and 1.4 ng/g for Pd respectively. The content of Re was determined in the reference materials RP-1 and Zh-3, and in the sample of comparison OPY-1.Предложена методика определения элементов платиновой группы (ЭПГ) Ru, Rh, Pd, Ir, Pt и Re в геологических образцах в диапазоне концентраций от 0.1 нг/г до 10 мкг/г, а также Os в перидотитах на уровне нг/г методом масс-спектрометрии с индуктивно связанной плазмой с внешней градуировкой и без химического удаления Zr и Hf. Подготовка проб основана на их кислотной деструкции в открытых системах после обжига с последующим доплавлением нерастворимого остатка с NH4F и отделением матричных элементов на катионите КУ-2-8 (фирма Токем, Россия). Измерения выполнены на масс-спектрометре высокого разрешения Element 2 (Finnigan MAT, Германия). Правильность определения содержания ЭПГ на уровне мкг/г подтверждена сравнением полученных результатов с аттестованными значениями для двух государственных стандартных образцов (ГСО) руды пирротиновой сплошной РП-1 и руды сульфидной медно-никелевой Ж-3, а для содержания аналитов на уровне нг/г – анализом международного образца сравнения перидотита OPY-1 (GeoPT-20), разрабатываемого Международной Ассоциацией Геоаналитиков (IAG). Значения пределов обнаружения, рассчитанные c учетом величины контрольного опыта и его стандартного отклонения (при переведении навески 1 г в 50 мл) составили: для Ru – 0.13 нг/г, Rh – 0.09 нг/г, Pd – 1.4 нг/г, Re – 0.07 нг/г, Os – 0.02 нг/г, Ir – 0.09 нг/г, Pt – 1.0 нг/г. Определены концентрации Re в ГСО РП-1, Ж-3 и OPY-1

On the Theory of Vibronic Superradiance

The Dicke superradiance on vibronic transitions of impurity crystals is considered. It is shown that parameters of the superradiance (duration and intensity of the superradiance pulse and delay times) on each vibronic transition depend on the strength of coupling of electronic states with the intramolecular impurity vibration (responsible for the vibronic structure of the optical spectrum in the form of vibrational replicas of the pure electronic line) and on the crystal temperature through the Debye-Waller factor of the lattice vibrations. Theoretical estimates of the ratios of the time delays, as well as of the superradiance pulse intensities for different vibronic transitions well agree with the results of experimental observations of two-color superradiance in the polar dielectric KCl:O2-. In addition, the theory describes qualitatively correctly the critical temperature dependence of the superradiance effect.Comment: 8 pages, 1 figur