The decay scheme of the 3-s Isomer of100Nb and the properties of levels in100Mo

Theβ ^? decay of the longer-lived isomer in¹⁰⁰Nb has been studied at the fission-product separator JOSEF. Measurements ofγ-ray singles spectra, ofγ-γ coincidences and ofγ-γ angular correlations have been performed. A value oft _1/2=2.99(11)s has been determined for the isomer which probably hasI ^π=4⁺ or 5⁺. A scheme of the levels of¹⁰⁰Mo which are populated in the decay of this isomer has been established. Information on the spins of several states of¹⁰⁰Mo has been obtained. Thus,I=0 levels have been identified at 1,505, 2,038 and 2,087 keV. The mixing ratios have been determined for the 2₂ ⁺→2₁ ⁺ and 2₃ ⁺→2₁ ⁺ transitions. The results provide evidence for a vibrational structure of¹⁰⁰Mo with separate bands based on the ground state and on the first excited 0⁺ level.     

Rotation-vibration spectrum of CH3F in the range 2000–2100 cm−1

The spectrum of CH₃F between 2000 and 2100 cm^?1 has been investigated under high resolution (0.025 cm^?1). Three parallel bands have been analyzed: 2ν₃ of ¹²CH₃F for which the rotational K structure has been studied, 3ν₃-ν₃ of ¹²CH₃F, and 2ν₃ of ¹³CH₃F. The band center of the main band 2ν₃ of ¹²CH₃F has been found at 2081.383 cm^?1.     

Mössbauer spectroscopic study on polyacetylene doped with iodine

The ¹²⁹I Mössbauer effect has been applied to polyacetylene films of cis-(CHI_0.23)_x as prepared and cis-(CHI_0.20)_x led under dynamic evacuation. It has been clarified that both films contain linear I^?₅ and I^?₃ with symmetric charge population and that the fraction of I^?₃ increases after evacuation. The mechanism of electrical conductivity in iodine-doped polyacetylene has been discussed on the basis of the chemical form and the dynamic behavior of the anion species.     

Relationship between the thermal expansion coefficient, plasmon energy, and bond length of ternary chalcopyrite semiconductors

A simple relation between the average bond length and plasmon energy, that is, d=15.30(?ω_p)^−2/3, has been proposed for A^IIB^IVC^V₂ and A^IB^IIIC^VI₂ chalcopyrite semiconductors. The average linear thermal expansion coefficient (α_L) of these semiconductors has been calculated using plasmon energy data. The linear expansion coefficients (α_a) and (α_c) of the lattice parameters a and c, respectively, have also been calculated. The calculated values of d, α_L, α_a and α_c have been compared with the experimental values and the values reported by different workers. A fairly good agreement has been obtained between them.     

The deformation of the ground and excited states in the Ag and Sn nuclei

The microscopic calculation of the potential energies in the ground and excited states of Ag and Sn nuclei has been performed. The single particle Nilsson potential and the shell correction Strutinski method have been used. The weak sensitivness to nonaxial deformation has been found for even neighbours of these nuclei. The small tendency towards prolate deformation of the ground and excited one-quasiparticle states originating from theg _9/2 proton subshell in^101–105Ag odd isotopes has been noticed. The behaviour with quadrupole e and hexadecapole ε₄ deformation of the ground and two-quasiparticle excited 0⁺ states originating from thed _5/2,g _9/2 andg _7/2 proton subshells andh _11/2 neutron subshell in^112–118Sn has been investigated. The small quadrupole deformation of the excited 0⁺ states has been found what is in agreement with the experimental data concerning the rotational bands build on the first excited 0⁺ states in Sn isotopes.     

The out-of-plane vibrational modes of chlorobenzene in its ground and first singlet excited states

The study of 2699 Å electronic band system of chlorobenzene has been extended to extract out all the six b₁ and three a₂ modes in both the ground state (^eA₁) and the electronically excited first singlet state (^eB₂). The procedure of the extraction of these modes on the basis of observed sequences, cross-sequences, and overtones has especially been elaborated. Strong Fermi interaction has been observed between the vibrational level ν′_6b and combination level ν′_16a + ν′_16b in ^eB₂ state. The uniqueness of the assignments of the modes has been critically discussed.     

Levels in154Eu populated by thermal neutron capture

The level scheme of¹⁵⁴Eu has been investigated by means of thermal neutron captureγ-rays and conversion electrons. The high energyγ-ray spectrum from thermal neutron capture in enriched¹⁵³Eu has been studied in the energy range of 5700 to 6500 keV. Low energyγ radiation has been observed with Ge(Li) and Si(Li) detectors from 5 to 300 keV and conversion electrons have been measured from 15 to 300 keV. Low energy (n, γγ) coincidences and half lives of transitions have been measured. The data, combined with three very recent studies of the 8^? isomer decay in¹⁵⁴Eu has led to the construction of a level scheme with 12 excited levels. Nuclear Reaction¹⁵³Eu(n, γ),E _n =thermal, measuredE _γ ,I _γ ,E _ce ,I _ce ,γγ-coincidence, halflives,¹⁵⁴Eu deduced levels.     

Diode laser spectrum and analysis of the 882-cm−1 band of s-tetrazine

A high-resolution diode laser spectrum of the 882-cm^?1 band of s-tetrazine has been obtained. A complete rotational analysis of this band, incorporating quartic and sextic centrifugal distortion coefficients, has been carried out. The rotational constants A, B, and C have been determined with an accuracy better than 10^?5 cm^?1. The analysis has shown the band to be A-type and, on this basis, the vibrational assignment of this band has been revised from ν₁₂ to ν₁₄.     

Search for a narrow resonance in 6Be with the 4He(3He,n) reaction

The ⁴He(³He, n)⁶Be reaction has been investigated at 36.20 MeV bombarding energy in search for a narrow resonance near the ³He-³He threshold which has been proposed as a possible explanation for the missing solar neutrinos in Davis' experiment. Neutrons have been detected at θ_b = 0° with an effective resolution < 25 keV in the c.m. system, in coincidence with protons emitted at θ_p = 50°. No indication for the existence of such a resonance has been found and an upper limit (dσ/dω)_res ≦ 7.5 μb/sr has been established.     

Deperturbation study of the 0–1 band of the d3Πi-b3Πr transition of the SiO molecule

The structure of the (0–1) band of the d³Π_i-b³Π_r system of SiO has been photographed under high resolution with a chemiluminescent flame source, and a rotational analysis has been carried out. All theoretically predicted 27 branches of the d³Π_i-b³Π_r transition have been identified. The upper-state level is shown to be perturbed by the v = 23 level of the A¹Π state. Due to mixing of the A¹Π with the d³Π, the (23-1) band of the A¹Π-b³Π_r transition has also been observed. The deperturbed molecular constants of the d³Π_i and A¹Π levels have been evaluated.     

Analysis of the microwave rotation spectrum of silyl cyanide,SiH3CN,in its ground and vibrationally excited states

The rotational spectrum of silyl cyanide, SiH₃CN, has been studied by microwave spectroscopy. A detailed analysis of the transitions in the excited states of the ν₃, ν₄, ν₇, and ν₈ modes has been carried out. In particular the v₈ = 1, 2, 3, and 4 vibrational satellites have been subjected to a complete vibration-rotation analysis. Ground state transitions of ²⁸SiH₃¹²C¹⁴N, ²⁹SiH₃¹²C¹⁴N, ³⁰SiH₃¹²C¹⁴N, ²⁸SiH₃¹³C¹⁴N, and ²⁸SiH₃¹²C¹⁵N have all been studied in natural abundance. The overall study has yielded a large amount of detailed vibration-rotation data. The effects of quadrupole interactions have been taken into account. To confirm the analysis, computer simulated spectra have been compared with those observed.     

High-resolution infrared spectra of NCCN and NCCN

High-resolution spectra of ¹⁵N¹²C¹²C¹⁵N and ¹⁴N¹³C¹³C¹⁴N have been measured and analyzed from 200 to 3600 cm⁻¹. All the vibrational levels below 900 cm⁻¹ have been observed and characterized. The Fermi resonance between ν₂ and 2ν₄ has been studied and the resonance constant has been determined for several cases. Several Σ⁻ states have been directly observed for the first time for each isotopomer, the (0001111)0f, (0011111)0f, and (0002222)0f states. The pattern of the energy levels for clusters of l-type resonance coupled levels, such as 0001131,3, has been determined for cyanogen for the first time. Among other things this involved the determination of the vibrational l-type resonance constant, r₄₅. Many of the power series constants, α_i and x_ij, and higher order constants have been determined.     

Evaluation of the rotational temperature of N+2(B2∑+u) in an R.F. discharge at moderate pressure in nitrogen: A comparison of methods

The rotational temperature of the N⁺₂(B²∑⁺_u → X²∑⁺_g) first negative system produced in an r.f. discharge has been evaluated according to various methods and a comparison of the results has been made.     

The high-resolution infrared spectrum of HBF2: The 201 band near 1164 cm−1

The type-B totally symmetric stretching fundamental ν₂ (near 1164 cm⁻¹) of difluoroborane has been recorded. Rotational and centrifugal distortion constants have been evaluated for the two isotopic species H¹⁰BF₂ and H¹¹BF₂, in both the ground and 2¹ levels. The spectrum has been found to be regular, with no perturbations and no new information on the position of the missing fundamental ν₆.     

Valence state of manganese ions in the La1−α BiLaβMnLa1−δ OLa3±γ ceramics

The valence state of the Mn ions in ceramic samples of the La_1?α BiLa_βMnLa_1?δ OLa_3±γ composition (LBMO) has been studied using the X-ray photoelectron spectroscopy. The presence of Mn³⁺ and Mn⁴⁺ ions in these compounds has been shown. The relative content Mn³⁺/Mn⁴⁺ has been determined by means of fitting the experimental Mn 2p spectra by the superposition of theoretical spectra of Mn³⁺ and Mn⁴⁺ ions. The elemental composition of the samples has been determined by the X-ray photoelectron spectroscopy and electron probe microanalysis. It has been established that the relative content of Mn⁴⁺ ions correlates with parameter δ, which characterizes the deviation of the actual elemental composition of the La_1?α BiLa_βMnLa_1?δ OLa_3±γ ceramics from stoichiometry La_{1 ? x} Bi _x MnO₃.     

Millimeter-wave spectroscopy of rare isotopomers of HC5N and DC5N: determination of a mixed experimental-theoretical equilibrium structure for cyanobutadiyne

Cyanobutadiyne has been produced by gas phase copyrolysis of pyridine and phosphorus trichloride in a flow reactor. The yield of the reaction is sufficiently good to allow the detection of rotational transitions of the ¹³C and ¹⁵N containing species in natural abundance. Normal pyridine and its fully deuterated variant have been used as precursors, making it possible to study the ground-state rotational spectra of 14 isotopomers in the millimeter wave region. Very accurate values of the rotational and quartic centrifugal distortion constants have been obtained for all the isotopic species investigated, and in addition the sextic distortion constant has been precisely determined for the most abundant variants H¹²C₅¹⁴N and D¹²C₅¹⁴N, for which the measurements have been extended up to 460 GHz. A mixed experimental-theoretical equilibrium structure has been evaluated for cyanobutadiyne combining experimental ground-state rotational constants with theoretically computed zero-point contributions. The r_e geometry is compared with operationally defined purely experimental structures, namely r₀, r_s, and r_m⁽¹⁾ molecular structures.     

Mössbauer study of Zn2+ and Sn4+ additives in Nickel ferrites

The Mössbauer study of Fe⁵⁷ in polycrystalline solid solutions of Ni_{1 + x ? y}Zn_ySn_xFe_{2 ? 2x}O₄ (y = 0.1, 0.3, 0.5 and x = 0.1 to 0.5 with x varying in steps of 0.1) has been made. The present work has been aimed at investigating the variation of isomer shift, nuclear magnetic field at Fe⁵⁷ nuclei and ionic distribution at tetrahedral and octahedral sites when the concentration of Zn²⁺ and Sn²⁺ ions is successively increased in nickel ferrites. The ionic distribution in samples having low tin concentration has been explained on the basis of Neel's molecular field model whereas the ionic distribution of samples having high tin and zinc concentration has been explained on the basis of formation of isolated superparamagnetic clusters at the octahedral site. It has been inferred that a larger substitution of zinc and tin ions enhances relaxation effects.     

Study of the ν2 + ν3 and 2ν6 infrared bands of CH379Br and CH381Br

The rotational analysis of the ν₂ + ν₃ band, centered around 1912 cm^?1, and of both components 2ν₆^±2 and 2ν₆⁰, centered about 1912 and 1904 cm^?1, respectively, has been carried out from a Fourier transform spectrum having a resolution limit of 0.005 cm^?1. A standard deviation of about 0.001 cm^?1 was obtained for about 750 lines of the unperturbed 2ν₆^±2 component for both isotopic species. The ν₂ + ν₃ band, stronger than 2ν₆^±2, is perturbed by two resonances: a Coriolis resonance with the very weak ν₃ + ν₅ band, no line of which has been observed, and an anharmonic resonance with 2ν₆⁰, only four K subbands of which have been observed. For both isotopic species, a standard deviation of about 0.002 cm^?1 has been obtained for about 750 lines of ν₂ + ν₃ and 2ν₆⁰.     

The high-resolution infrared spectrum of HBF2: The 401 band near 926 cm−1

The type-C out-of-plane bending fundamental ν₄ (near 926 cm⁻¹) in the infrared spectrum of gaseous difluoroborane, HBF₂, has been recorded at high resolution. Rotational and centrifugal distortion constants have been obtained for the two isotopic species H¹⁰BF₂ and H¹¹BF₂ in both the ground and 4¹ levels. A small rotational perturbation in the 4¹ level of H¹¹BF₂ has allowed an estimate of the position of the ν₆ fundamental, which so far has not been observed directly.     

Difference frequency laser spectroscopy of HCNH+: Observation of the isotopic species and the hot bands

The infrared spectra of the isotopic species of HCNH⁺, HCND⁺ and H¹³CNH⁺, have been observed with a difference frequency laser system. The r_s structure of the ion has been determined by combining the rotational constants of the normal species and DCNH⁺ previously obtained. Two hot bands of the normal species, presumably ν₁ + ν₄ ← ν₄ and ν₁ + ν₅ ← ν₅, have also been observed and the spectroscopic constants have been determined.