Level structure of 42K from the 41(n, γ) and 41K(d,p) reactions

The γ-ray spectrum emitted after thermal neutron capture in ⁴¹K has been measured with pair and Ge(Li) spectrometers at the ILL high-flux reactor. About 630 transitions have been assigned to the decay of 133 excited states in ⁴²K. The level energies have been determined with a precison of 20 ppm; the neutron binding energy was determined to be E_B = 7533.82(15) keV. On the basis of the many transitions to known states, several spin-parity assignments have been made. In addition, high-resolution proton spectra of the reaction ⁴¹K(d,p) have been taken at 20MeV deuteron energy with the München Q3D spectrometer. These data have been essential in establishing the newly-found levels and in differentiating between primary and secondary transitions in the (n, γ) work. A statistical analysis of the level density and relative strengths of primary transitions is given.     

214Po: A γ-γ and γγ(θ) Coincidence study

Extensive γ-γ coincidence measurements have been made on γ rays accompanying theβ ^? decay of²¹⁴Bi using a conventional GeGe coincidence spectrometer. A total of 33 new γ transitions among levels of²¹⁴Po have been established. Twenty-three previously reported but unplaced transitions have now been assigned in the level scheme. In addition to confirming 56 previously proposed levels, four new levels are established at 1015.05, 1712.98, 3003.5 and 3160.5 keV. Directional correlation measurements have been made on six weak cascades which have the first excited state in common. Mixing ratios have been deduced for the transitions concerned.     

An internal conversion study of the decay of193Au

The internal conversion spectrum following the decay of¹⁹³Au has been studied in the electron energy region 0.8 to 700 keV, with the use of high-resolution magnetic beta-ray spectrometers. Several not previously reported transitions have been estabblished. Multipolarities and mixing ratios have been deduced fromK/L and subshell intensity ratios, and the majority of the transitions were found to be ofM1 and/orE2 characters. A revised level scheme for¹⁹³Pt, which consistently accomodates most transitions, has been constructed. Tentative spin-parity values have been assigned to all levels.     

The high pressure phase transitions in KF and RbF

The high pressure B1 ? B2 transitions in KF at ~ 40 kbar and RbF at ~ 30 kbar have been studied using hydrostatic X-ray diffraction. No other transitions have been observed. The addition of the $\text{ΔV}\text{V}$ for these transitions to the already existing body of literature on B1–B2 transitions in alkali halides permits an extension of Pauling's theory to larger values of radius ratios. It also permits the modified Born criterion for predicting phase transitions to be further verified. Values of ionic radii for 8 coordination we suggest are 1.33 Å for F^?, 1.84 Å for Cr^?, 2.00 Å for Br^? and 2.27 Å for I^?.     

The (n, α) reaction on 11B induced by 14.4 MeV neutrons

The ¹¹B(n, α)⁸Li reaction has been studied at 14.4 MeV in a geometry that allows simultaneous detection of the emitted and recoil particles. The angular distributions have been measured for the transitions to the ground and first excited states of the ⁸i nucleus and compared with PWBA for knock-on and heavy-particle pick-up processes. The total cross sections for the respective transitions have been deduced.     

A high resolution visible spectrum of iridium monophosphide

Laser induced fluorescence spectra of iridium monophosphide, IrP, have been obtained at low and high resolution in the blue region of the visible spectrum. Two electronic transitions were observed with origins near 459.6 and 471.9 nm. Three vibronic bands in each of these transitions have been observed at high resolution allowing for full characterization of the states. A J-independent doubling of the rotational lines has been ascribed to nuclear electric quadrupole coupling in the ground state. Multireference configuration interaction (MRCI) calculations have been performed in order to confirm the nature of the ground state and aid in the assignment of the excited states. The two observed transitions have been assigned as the [21.7]¹Σ⁺-X¹Σ⁺ and the [21.2] ³Σ⁺-X¹Σ⁺ electronic systems based on comparison with the theoretical calculations. The v + 2 level of each of these electronic transitions was found to be heavily perturbed and a successful deperturbation analysis was performed allowing for a complete global fit of the data.     

An investigation of centrifugal distortion in the microwave spectrum of formamide

Measurements of the microwave spectrum of formamide have been extended in order to account accurately for the effects of centrifugal distortion. A total of 22 new transitions involving J ≤ 29 have been measured for ¹⁴NH₂¹²CH¹⁶O in the ground vibrational state. Combined with previous observations, these transitions have been fit to a model containing five quartic distortion terms and seven sextic terms with a rms deviation of 64 kHz. A large number of resolved quadrupole shifts were fit with an rms deviation of 42 kHz. The remainder of the spectrum for J ≤ 30 has been calculated with standard deviations less then 3 MHz. Correct weighting of the observed transitions has been found to be important.     

Erzeugung 21 neuer kurzlebiger Isomere durch Kernphotoreaktionen

Irradiation of 28 selected elements with 22.5 MeV bremsstrahlung led to the production of numerous short-lived isomeric states by photonuclear reactions. At least 21 of the observed isomeric transitions seem not to have been reported in the literature thus far. The energies and half-lives of the observed transitions were measured using a conventional scintillation spectrometer. The half-lives of the newly discovered isomeric states are in the region between 5·10^?6 and 6·10^?2 seconds. Isotopic assignments and multipolarities of the observed transitions have not yet been established.     

Levels and transitions in125Te

Gamma transitions and levels of¹²⁵Te following the decay of¹²⁵Sb have been studied using Ge(Li) detector and NaI(Tl)-NaI(Tl) sum-coincidence spectrometer incorporated with a fast-slow coincidence circuit. In all, twenty five gamma rays have been reported, out of which two weak gamma rays with energies 366·0 and 402·0 keV have been observed and confirmed for the first time. These gamma rays have been fitted by assigning a new level of 402 keV energy. An ambiguous transition of energy 122·1 keV has also been confirmed. No evidence was found for the existence of 145·9, 315·0, 489·8, and 497·4 keV transitions. The accurate intensities for various transitions have been determined.     

High resolution spectrum of the ν5 band of nitric acid (HNO3) near 880 cm−1

Tunable diode lasers have been used to measure the spectrum of HNO₃ from 853 to 892 cm^?1. A Fermi interaction with the nearby 2ν₉ state perturbs some of the transitions and causes some problems in the analysis, but several hundred lines have been assigned and fit to a set of band constants with a standard deviation of 0.0007 cm^?1. The measurements include most of the P branch, the strongest lines of the Q branch, and some R-branch transitions. Only A-type transitions have been identified and any B-type transitions must be much weaker.     

Levels in172Yb from the172Lu β-decay

The single and coincidence gamma-ray spectra from the decay of¹⁷²Hf and¹⁷²Lu isotopes have bsen studied using various Ge(Li) detectors. The precise energies and intensities of gammarays have been obtained. Six weak transitions have been observed for the first time and some of transitions reported previously have not been confirmed. The structure of the¹⁷²Yb excited levels is discussed in terms of the unified model.We want to thank Dr. J.Adam, the head of Nuclear Spsctroscopy Department of our Institute, for his continuous support.     

Fluorescence spectra of matrix-isolated praseodymium triodide molecules

Fluorescence spectra of PrI₃ molecules isolated in Ar and Xe matrices have been measured for the first time. More than 40 transitions have been measured using Hg excitation and have been assigned to transitions within the 4f² configuration.     

On-line nuclear orientation of70As

On-line nuclear orientation was performed on⁷⁰As. Anisotropy data have been obtained at 8.7mK for 29 gamma transitions. Multipole mixing ratios have been extracted for 17 transitions. Our results are in good agreement with existing data for the ten previously measured transitions. Our first time data for the 1496 keV, 2⁺→2⁺ γ-ray suggest the 2536 keV level is a good candidate for a mixed symmetry level.     

Die γ-Spektren von Tc95, Tc95m und Tc96

Theγ spectra of Tc⁹⁵ (20 h), Tc^95m (62 d), and Tc⁹⁶ (4.3 d) have been investigated using Li-drifted germanium counters. The observedγ transitions in the decay of Tc⁹⁵ and Tc^95m are in agreement with earlier investigations except for 6 transitions at 204, 680, and 840 keV in Tc⁹⁵ and at 970, 1390, and 1630 keV in Tc^95m reported previously which have not been confirmed. In the spectrum of Tc⁹⁶ new transitions at 437, 462, 1094, 1200, and 1505 keV have been identified. The level scheme of Mo⁹⁶ is discussed in respect of these results.     

Optical transitions of Eu2+ IONS in RbMgF3 crystals

Because of the need for tunable solid state lasers in the blue region of the spectrum, a number of recent studies have been on the optical properties of Eu²⁺ in various crystals lattices. The absorption and emission from Eu²⁺ ions in fluoride hosts arise from both 5d→4f and 4f→4f transitions. The absorption is in the ultra-violet and the emission is in the blue. The 4f-4f transitions are very sharp and are located around 360 nm. The 5d→4f emission bands at 405 nm and 525 nm are broad and host lattice dependent. We have studied the temperature dependence of the optical properties of RbMgF₃:Eu²⁺ including absorption, emission, and excitation. In the case of the emission studies both temperature dependence and the lifetimes of the transitions have been measured. These transitions are discussed in detail.     

Study of the radioactive decay of192Ir

Theβ ^? and electron capture decays of¹⁹²Ir to the levels of¹⁹²Pt and¹⁹²Os respectively have been investigated to verify the existence of some of weak gamma transitions reported earlier. Gamma-gamma directional correlation measurements have been done for 13-cascades. Multipole admixture of 201, 283, 485 keV gamma transitions in¹⁹²Os and 296, 308, 416, 604 keV gamma transitions in¹⁹²Pt have been deduced. A spin value of 4⁺ has been reaffirmed on the basis of almost zero intensity of 1201 keV gamma ray (4⁺→0⁺) and 416→(468)→316 keV cascade directional correlation measurements.     

Die Anregungszustände des79Br

Previous investigations of nuclear resonance fluorescence from⁷⁹Br have been improved by using a Ge-detector. In addition, energies and intensities of theγ transitions initiated by the decay of⁷⁹Kr have been remeasured. Coincidences between theγ transitions were investigated using two 40 ccm Ge-detectors. 14γ transitions unknown up to the present have been identified. A level scheme having 12 excited states is proposed. Unique assignments of spin and parity to the 7 lowest states became possible by the present and former experimental data.     

The far-infrared spectrum of fluoroform (CHF3)

The far-infrared spectrum of fluoroform has been recorded in the region between 7 and 60 cm⁻¹ at a resolution of 0.002 cm⁻¹. More than 1400 rotational transitions in the ground state have been measured and assigned up to J″ = 80. Simultaneous analyses of these measurements and of microwave and millimeter-wave data reported previously have been performed. Improved values of the ground state rotational and centrifugal distortion constants, including the sextic distortion constants reported for the first time, have been obtained. Rotational transitions in a few low-lying vibrational states have also been observed.     

A γγ coincidence study of transitions in239Np and239Pu from decay of243Am

Gamma-gamma coincidences and singles measurements with Ge detectors have been made on transitions in²³⁹Np and²³⁹Pu. Eighteen transitions in²³⁹Pu and three in²³⁹Np have been verified by coincidence data. High resolution singles measurements were made and new values for the energy and intensities ofγ-rays below 350 keV were obtained.     

Microwave spectrum of formic acid and its isotopic species in D, 13C and 18O. Study of Coriolis resonances between ν7 and ν9 vibrational excited states

In the investigation of the 8 → 280 GHz region, 241 and 57 transitions of H¹²COOH and DCOOH, respectively, have been assigned to the ν₇ and ν₉ vibrational states coupled by a strong Coriolis resonance. The numerical analysis based on Watson's theory of centrifugal distortion coupled with the addition of Coriolis interaction allows us to obtain a set of parameters which fits the transitions well. The rotational spectra of the isotopic species HCOOD and DCOOD have also been investigated. In this investigation 55 and 67 transitions have been assigned to the ν₇ and ν₉ vibrational states of these two molecules, respectively. A very weak Coriolis resonance was detected. Two non-rigid independent rotors were thus employed and gave us a set of parameters which fits the transitions quite well. The rotational spectrum of the ground state of H¹²COOH, H¹³COOH, HCOOD, DCOOH, H¹²C¹⁶O¹⁸OH, and H¹²C¹⁸O¹⁶OH have been reinvestigated and a set of improved parameters was obtained for each species.