Comparison of theoretical and experimental red and near infrared absorption spectra in overheated potassium vapour

The K₂ molecular spectra have been theoretically and experimentally investigated in the wavelength range between 550 nm and 1100 nm and at the temperatures between 650 K and 1100 K. Semiclassical theoretical simulations were performed using the most recent data for the potential energy curves for the K(4S)+K(4S) and K(4S)+K(4P) systems and the relevant dipole transition moments. The measurements of the corresponding spectra were performed by a spatially resolved absorption method in an inhomogeneous overheated potassium vapour generated in a heat pipe. Both theoretical and experimental investigations confirmed that the reduced absorption coefficients of the potassium diffuse triplet bands at 575 nm, 721.5 nm and 1095 nm are practically independent of temperature in a wide temperature range. The obtained data for the reduced absorption coefficients of these bands can be used for a simple and accurate determination of potassium atom number densities in the range from 5×10¹⁶ cm^-3 to 5× 10¹⁸ cm^-3.     

Multiple trapping sites for potassium atoms in argon matrices

Argon crystals were dopes with 0.2 ppm of ⁴¹K through the nuclear reaction ⁴⁰Ar(n, β^-)⁴¹K. The X-band electron spin resonance spectrum of ⁴¹K was observed. The recorded spectra clearly show the existence of different trapping sites for potassium in argon. Zero-field hyperfine splittings and g-values of potassium on these sites are determined.     

Determination of potassium, calcium and chlorine in some vegetables by EDXRF

Total concentration of potassium, calcium and chlorine was determined in the presence of each other and irrespective of the nature of their compounds, in the leaves of Urticae dioico L. and Spinacia oleracea L. (spinach) plants by EDXRF. The enhancement of potassium K X-rays due to calcium K X-rays and enhancement of chlorine K X-rays due to potassium and calcium K X-rays present in the samples were avoided by selective secondary excitation method of the samples. Our results were compared with other experimental results.     

Gamma rays from thermal-neutron capture in natural and K enriched potassium

Gamma rays following thermal-neutron capture in natural and in ³⁹K enriched potassium have been investigated with a Ge(Li) and a Ge(Li)-NaI spectrometer. In the ³⁹K(n,γ)⁴⁰K reaction 222 γ-rays were found, of which 187 could be fitted into the level scheme of ⁴⁰K. Fifteen γ-rays could be ascribed to the ⁴¹K(n, γ)⁴²K reaction. Excitation energies of 54 levels in ⁴⁰K and of 9 levels in ⁴²K have been determined with 0.2−1.0 keV errors. The Q-values of the ³⁹K(n, γ)⁴⁰K and ⁴¹K(n, γ)⁴²K reactions are Q = 7799.7 ±0.8 keV and 7533.9±1.2 keV, respectively.     

Comparative analysis of cesium and potassium uptake in onion <Emphasis Type="Italic">Allium cepa</Emphasis> L.

Cesium uptake in onion (from 0.3 mM CsCl solution traced with ¹³⁷CsCl) has been examined. The highest uptake occurred at pH 4–5 and it decreased with increasing pH. The intensity of Cs translocation depended on acidity of the solution. For acidic solutions, translocation of cesium into bulbs and leaves was greater than in case of alkaline solutions, where most of the cesium remained in the roots. Addition of potassium into the solutions (millimolar K concentrations) inhibits Cs uptake. The potassium pH-influx/efflux characteristic does not coincide with the Cs uptake.     

Potassium and potassium oxide monolayers on the platinum (111) and stepped (755) crystal surfaces: A LEED,AES, and TDS study

The adsorption of potassium and the coadsorption of potassium and oxygen on the Pt(111) and stepped Pt(755) crystal surfaces were studied by AES, LEED, and TDS. Pure potassium adlayers were found by LEED to be hexagonally ordered on Pt(111) at coverages of θ = _K0.9–;1. The monolayer coverage was 5.4 × 10¹⁴K atoms/cm² (0.36 times the atomic density of the Pt(111) surface). Orientational reordering of the adlayers, similar to the behavior of noble gas phase transitions on metals, was observed. The heat of desorption of K decreased, due to depolarization effects, from 60 kcal/mole at θ_K <0.1, to 25 kcal/mole at θ_K = 1 on both Pt(111) and Pt(755). Exposure to oxygen thermally stabilizes a potassium monolayer, increasing the heat of desorption from 25 to 50 kcal/mole. Both potassium and oxygen were found to desorb simultaneously indicating strong interactions in the adsorbed overlayer. LEED results on Pt(111) further indicate that a planar K₂O layer may be formed by annealing coadsorbed potassium and oxygen to 750 K.     

Raman spectra of potassium, rubidium, and thallium hydrogen phthalates

The polarized Fourier-transform Raman spectra of oriented single crystals of K, Rb, and Tl hydrogen phthalates, as well as of deuterated potassium hydrogen phthalate, are studied in the range 50–3300 cm^?1 in different scattering geometries. The frequencies of internal vibrations in the spectra of these compounds are assigned to vibrations of the orthophenylene and carboxyl groups. The replacement of K with Rb or Tl leads to an insignificant low-frequency shift of vibrations. A multiband structure of OH(D) stretching vibrations is observed in the range 1900–2800 cm^?1 in the spectra of all hydrogen phthalates, which is caused by Fermi-resonance interactions. A number of additional bands are observed in the spectrum of deuterated potassium hydrogen phthalate, which indicates that deuterium atoms partially replace hydrogen atoms in both the orthophenylene and the carboxyl groups.     

EDXRF determination of impurities in potassium dihydrogenphosphate single crystals and raw materials

A fast and simple preconcentration procedure for recovering various cation impurities from potassium dihydrogenphosphate (KDP) single crystals and raw materials, followed by energy‐dispersive X‐ray fluorescence analysis (EDXRF), is described. The technique is based on the adsorption of metal 8‐hydroxyquinoline complexes from aqueous solutions of KDP on activated carbon, separation of the concentrate on a Nuclepore filter and subsequent determination by EDXRF. To fix activated carbon powder on a filter surface, an amount of 1‐hexadecanol is added to the KDP solution during the preconcentration procedure. The optimum conditions for the best recovery of the impurities were established. It was shown that a preconcentration factor of 100 can be achieved and the detection limit for a number of elements was down to 0.01 µg g^?1. The relative standard deviations were 6–17% for element concentrations of 0.2 µg g^?1. The method was successfully applied to the determination of Fe, Co, Cu, Ni, Zn, Mn, Ti and Bi in KDP single crystals and raw materials. Copyright © 2005 John Wiley & Sons, Ltd.     

Diffusion of sodium,potassium, calcium,manganese, and radon in tuff and clinoptilolite under leaching

Nuclear physics methods are used to determine the diffusion coefficients of Na, Ca, Mn, K, and ²²²Rn in clinoptilolite (Sokirnitsa occurrence, Ukraine) and in natural tuff (Yucca Mountain, Nevada, United States) and in tuff irradiated by γ-quanta (E _max = 23 MeV) to a dose of 10⁷ Gy at a leaching temperature of 37°C. The diffusion coefficients of sodium and potassium in clinoptilolite are found to differ considerably: 4 × 10⁻¹⁷ and 2 × 10⁻²⁰ m²/s, respectively. This indicates the influence of aquacomplexes on the cation transfer. The diffusion coefficient of radon in these materials is determined: in clinoptilolite it equals 2.5 × 10⁻¹² m²/s.     

137Cs and 40K activity concentration measurements and elemental analysis in lichen samples collected from the Giresun province of northeastern Turkey

About 21 years after the Chernobyl accident, ¹³⁷Cs and ⁴⁰K activity concentration measurements using gamma-ray spectroscopy and elemental analysis using energy dispersive X-ray spectroscopy were performed in five different lichen species collected from the Giresun province of northeastern Turkey. Being a symbiosis of algae and fungi, lichens are mostly used for environmental measurements since the fungal partner is responsible for the uptake of necessary nutrients or harmful substances, such as heavy metals of radionuclides. The gamma activity results showed that ¹³⁷Cs, an artificial radionuclide released from the Chernobyl power plant accident, is still eminent in the environment of the province. The mean activity concentrations of ¹³⁷Cs and ⁴⁰K ranged from 24 to 254 with the mean value of 102 Bq kg^?1 and from 345 to 2103 with the mean value of 1143 Bq kg^?1 in dry weight. The results of the elemental analyses showed potassium, calcium, titanium, iron, tin, and barium in different concentrations.     

Nuclear Resonant Inelastic and Forward Scattering of Synchrotron Radiation by 40K

We achieved excitation of the first excited state of ⁴⁰K and confirmed both energy and lifetime. Furthermore, we observed nuclear resonant inelastic scattering by ⁴⁰K in a powdered KCl sample at room temperature using a high-resolution monochromator. The time spectrum of the nuclear resonant forward scattering was measured at 50 K. Our observations of nuclear resonant inelastic and forward scattering by ⁴⁰K make electronic and dynamic studies for potassium practical. The measurements of nuclear resonant scattering for the radioactive ⁴⁰K nuclide will enable and lead to further studies of other radioactive nuclides. This revised version was published online in August 2006 with corrections to the Cover Date.     

Natural radioactivity of paleozoic and mesozoic sedimentary rocks from the Upper Silesian Coal Basin borders (Poland) — in situ gamma ray measurements

Sedimentary rocks from the borders of the Upper Silesian Coal Basin are the most popular origin of building materials in whole Silesia region. In situ gamma ray spectrometry was used to determine the activity concentration of nuclides from U series, Th series and potassium ⁴⁰K in almost every kind of sedimentary rocks outcropping in the studied region. Measured activity concentration of particular nuclides such as ⁴⁰K, U series, and Th series are mostly not higher than average activity concentrations of these nuclides in the continental crust. However, there are some significant exceptions such as clays from Blanowice and Krasiejow. In spite of that there isn’t any reason to stop using these rocks as building or other industrial material sources.     

Spin-lattice relaxation of the O2 − molecule-ion in the potassium halides

An experimental and theoretical study of the spin-lattice relaxation (SLR) of the O₂ ^? molecule-ion in the potassium halides has been made. The SLR rate was measured by several methods between 1.32°K and 36°K with a 3 cm. ESR spectrometer. The results indicate a one phonon process with a large anisotropy dominates forT<2°K.T ₁ is much longer for the magnetic field parallel to the molecular axis. Detailed theoretical calculations indicate a new SLR process, namely phonon-induced libration of the molecular axis, can probably explain the field parallel case. The Van Vleck SLR process can account for the field-perpendicular case.     

Dielectric relaxation in hydroxyl doped potassium chloride

The dielectric constant and the dielectric loss of hydroxyl doped potassium chloride crystals have been explored in the temperature range between 1.5°K and 80°K with frequencies ranging from 10⁵ c. p. s. to 3.3×10⁸ c. p. s. The observed relaxation behavior is discussed in terms of one-phonon processes.     

Self-diffusion of potassium in potassium azide

The tracer sectioning technique was used to study the diffusion of potassium ions in melt grown single crystals of potassium azide. The temperature dependence of the diffusion coefficients in the range 85–254°C can be represented by D=(0·19±0·03) exp [(?0·80±0·06) eV/kT] cm²/sec. It appears that the cations are the predominant mobile species and that they diffuse by a vacancy mechanism with an enthalpy of migration of 0·80±0·06 eV.     

Natural radioactivity of paleozoic and mesozoic sedimentary rocks from the Upper Silesian Coal Basin borders (Poland) — <Emphasis Type="Italic">in situ</Emphasis> gamma ray measurements

Sedimentary rocks from the borders of the Upper Silesian Coal Basin are the most popular origin of building materials in whole Silesia region. In situ gamma ray spectrometry was used to determine the activity concentration of nuclides from U series, Th series and potassium ⁴⁰K in almost every kind of sedimentary rocks outcropping in the studied region. Measured activity concentration of particular nuclides such as ⁴⁰K, U series, and Th series are mostly not higher than average activity concentrations of these nuclides in the continental crust. However, there are some significant exceptions such as clays from Blanowice and Krasiejow. In spite of that there isn’t any reason to stop using these rocks as building or other industrial material sources.     

Radiocaesium pollution of fly agaric Amanita muscaria in fruiting bodies decreases with developmental stage

Amanita muscaria collected from a forested area in northern Poland in 2015 were analysed for activity concentrations of ¹³⁷Cs and ⁴⁰K. Total K concentration values were calculated from ⁴⁰K data. Mushrooms were grouped in six fruiting bodies size classes regarding to their developmental stage. The ¹³⁷Cs activity concentrations declined in A. muscaria as the fruiting bodies maturated. The contents of ⁴⁰K/K activity remained constant in caps at different developmental stage, while for stipes an increase was around twofold (⁴⁰K from 925?±?55 Bq kg^?1 dry biomass in the baby individuals and 1600?±?63–1700?±?53 Bq kg^?1 dry biomass in two oldest classes). A. muscaria is a weak accumulator of ¹³⁷Cs, while a steep drop in activity concentrations of this nuclide in the fruiting bodies as they maturate has not been reported earlier for mushrooms. Clearly, a fate of ¹³⁷Cs in A. muscaria is highly different from that of ⁴⁰K/K that is an essential element to fungi. In parallel, an observed increase in the content of ⁴⁰K/K in stipes of fruiting bodies with developmental state can be related to its ‘hardening’ and more fibrous nature with age and basic function to support the cap, but this has not been studied.     

Geological influence on the activity concentration of terrestrial radionuclides 226Ra, 232Th and 40K in the Jos Plateau,Nigeria

The Jos Plateau has been reported to have elevated levels of natural background radiation. A few earlier studies have measured the levels of natural radioactivity for specific locations in the area. Our interest is to investigate how geology of the study area influences the activity concentrations of natural radionuclides. Thus, the activity concentrations of terrestrial radionuclides in soil samples collected across the geological formations of the Jos Plateau were determined by gamma spectrometry technique. The mean activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were found to exceed their corresponding world reference values of 35, 40 and 400?Bq?kg^?1, respectively. Data were compared using statistical methods, analysis of variance (ANOVA) and post hoc tests. The results revealed in some instances significant influences of geological types on the activity concentrations in the area. The spatial distribution maps of activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were geostatistically interpolated by ordinary Kriging method using ArcGIS software.     

Determination of terrestrial gamma, 238U, 232Th and 40K in soil along fracture zones

²³⁸U, ²³²Th and ⁴⁰K concentrations in 72 soil samples from two major fault systems (North and East Anatolian Active Fault Sytems) in Turkey have been studied. However, terrestrial gamma radiation dose originated by natural radionuclides in soil was measured and compared with other measurements in literature for different countries. This extensive survey regarding U, Th and K radionuclide and terrestrial gamma dose measurement was carried out by means of NaI(TI) gamma spectroscopic system and a dose rate meter, respectively. The mean concentration of ²³⁸U, ²³²Th and ⁴⁰K in soil samples in NAFS is higher than determined in EAFS. The measured and calculated mean gamma dose rates in two fault systems are found to be higher than 57 nGyh⁻¹.     

Statistical relationship between activity concentrations of radionuclides 226Ra, 232Th, 40K,and 137Cs and geological formations in surface soil of Jordan

An extensive study was conducted to determine the activity concentrations of natural and artificial radionuclides ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs in soil samples of each governate of Jordan. A total of 370 samples have been measured using a high-purity germanium detector. The activity concentration for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs has mean values of 42?±?3, 23?±?3, 309?±?21, and 3.7?±?0.9 Bq kg^–1, respectively. The highest mean activity concentration for ²²⁶Ra was found to be 138?±?4 Bq kg^–1 in the Alkarak governate. In the Ajloun and Jarash governates, the highest mean activity concentration was 35?±?3 Bq kg^–1 for ²³²Th, and 14.2?±?1.9 Bq kg^–1 for ¹³⁷Cs, respectively. Geological influence on the activity concentrations was investigated using the one-way analysis of variance (ANOVA) and independent samples. The ANOVA results indicate that there are strong significant differences between the activity concentrations of ²³²Th, ⁴⁰K, and ¹³⁷Cs based on geological formations the radionuclides occur. The main contribution to gamma dose rate was due to ²²⁶Ra activity concentration. Radium equivalent and external hazard index are associated with a mean value of 98 Bq kg^–1, and 0.266, respectively.