High-temperature infrared spectrum of HCN near 3300 cm−2

The infrared absorption of HCN near the fundamental band at 3311 cm^?1 has been measured at temperatures up to 1200 K. Transitions involving high rotational states (up to J = 62) have been measured. These give an improved value for the sextic centrifugal distortion term H₀. Many hot-band transitions have been observed and assigned to transitions originating in vibrationally excited states up to 4000 cm^?1 above the ground state. These measurements give new data on vibrational states involving moderately high bending quantum numbers and indicate that new terms are needed to fit the ro-vibrational energy levels.     

High-resolution infrared measurements on HSOH: Analysis of the OH fundamental vibrational mode

High-resolution infrared measurements of the OH-stretching mode of oxadisulfane, HSOH, at 3625 cm⁻¹ have been recorded using a Bruker IFS 120 HR Fourier transform spectrometer. More than 1300 lines have been assigned to the ν(OH) fundamental vibration mode, which is a hybrid band showing a c-type perpendicular band and an a-type parallel band spectrum of an asymmetric rotor molecule. The splitting due to the torsional-tunneling has not been observed in this band. The band center position at 3625.59260(20) cm⁻¹ as well as rotational and centrifugal distortion constants for the ν(OH) vibrational excited state have been obtained from a least-squares fit analysis of a semirigid rotor. In addition the α_OH experimental vibration-rotation correction terms of the OH-stretching mode have been derived and compared to values used in an earlier semi-empirical calculation of the HSOH structure. All data are in very good agreement with high level ab initio calculations and confirm the assignment of an earlier matrix isolation spectrum at 3608 cm⁻¹ to the ν(OH) fundamental mode.     

Rotational and vibrational structure in the 288 nm band system of the FeCl2 radical

The laser excitation spectrum of the 288 nm band system of FeCl₂, formed in a free-jet expansion, has been recorded at a rotational temperature of approximately 10 K. Vibronic transitions are observed from the ground state to two close-lying excited electronic states that differ in inversion (g, u) parity. Two extensive progressions in the symmetric stretching vibration have been identified, referred to as Progressions A and B. The main features of Progression A, which is based on the band, are allowed transitions to the excited electronic state of ungerade symmetry. Progression B is built on the band and consists of vibronically induced transitions to the gerade excited state. A substantial decrease in the symmetric stretching vibrational wavenumber is observed on excitation . Local perturbations are found to cause relative shifts between the different isotopomers. Several vibronic bands have been recorded and analysed at rotational resolution for the three isotopomers Fe³⁵Cl₂, Fe³⁵Cl³⁷Cl, and Fe³⁷Cl₂ in natural abundance. All bands show perpendicular rotational structure of a linear molecule, and have been unambiguously assigned to a Ω = 5-4 transition, consistent with the inverted ⁵Δ_g ground state predicted by ab initio and DFT calculations. The zero-point averaged FeCl bond length is determined to be in the upper and lower electronic states. The results show that the molecule is linear in both states.     

Microwave spectrum,dipole moment,and structure of 3-aminopropanol

The microwave spectra of 3-aminopropanol and three of its deuterium substituted isotopic species have been investigated in the 26.5 to 40 GHz frequency region. The rotational spectrum of only one conformer has been assigned in which presumably a hydrogen bond of the OH---N type exists. The rotational spectra of a number of excited vibrational states have been observed and assignments made for some of these excited states. The average intensity ratio for the rotational transitions between the ground and excited vibrational states indicates that the first excited state is about 120 cm^?1 above the ground state.and the next higher state is roughly 200 cm^?1 above the ground vibrational state. The dipole moment was determined from the Stark effect measurements to be 3.13 ± 0.04 D with its principal axes components as |μ_a| = 2.88 ± 0.03 D, |μ_b| = 1.23 ± 0.04 D and |μ_c| = 0.06 ± 0.01 D. The possibility of another conformer where the hydrogen bond could be of NH---O type was explored, but the spectra of such a conformer could not be identified.     

Investigation of22Na excited states

Fourteen²¹Ne(p, γ)²²Na resonances have been observed in the rangeE _p =300–1,300 keV. Theγ-decay of all these resonances has been investigated by means of a 38 cm³ Ge(Li) detector. Energies and branching ratios of several bound states have been determined. TheQ-value was determined as 6,738.5±1.7 keV. Lifetimes of seven states were determined with the Doppler-shift attenuation method. The observed upper limit (τ _m ≦4 fs) of the lifetime for the 4,071 keV state, regarded as the analogue of the third excited state in²²Ne, and the transition observed from this state to the 1,528 keV state do not support the proposed rotational band structure of the²²Na low-lying states.     

Born-Oppenheimer breakdown effects and hyperfine structure in the rotational spectra of SbF and SbCl

Pure rotational spectra have been measured for the ground electronic states of SbF and SbCl. The molecules were prepared by laser ablation of Sb metal in the presence of SF₆ or Cl₂, respectively. Their spectra were measured with a cavity pulsed jet Fourier transform microwave spectrometer. Although both molecules have two unpaired electrons, they are subject to Hund’s coupling case (c), and have X₁0⁺ ground states. The spectra have been interpreted with the formalism of ¹Σ⁺ molecules. For both molecules spectra of several isotopomers have been measured in the ground and first excited vibrational states. Large hyperfine splittings attributable to both nuclear quadrupole coupling and nuclear spin-rotation coupling have been observed. A Dunham-type analysis has produced unusually large Born-Oppenheimer breakdown parameters, which are interpreted in terms of the electronic structures of the molecules.     

The centimeter and millimeter microwave spectra of butadiene sulfone and α,α′-D4 butadiene sulfone

Microwave measurements on the ground and first eight excited states of the ring-puckering vibration of butadiene sulfone have been extended to millimeter wavelengths. The microwave spectra of the same vibrational states of α,α′-D₄ butadiene sulfone have been observed. For both isotopomers the Coriolis interaction between the v = 0 and v = 1 states has been analyzed to give the energy separation between these two states. These data and the variation of the rotational constants have been used to derive reduced potential functions for the ring-puckering vibration. The barrier to ring inversion is 49(2) cm⁻¹ for butadiene sulfone and 44(2) cm⁻¹ for the α,α′-D₄ isotopomer. The ring-puckering vibrational dependence of the quartic centrifugal distortion constants, including a small dependence of Δ_J and δ_J, has been accounted for.     

Near infrared transitions between Rydberg states of nitric oxide: The 4f-F2Δ band at 1.71 μm

Several near infrared transitions between highly excited Rydberg (R) states of nitric oxide have been recorded at high resolution (0.15 cm^?1) with a SISAM interferometer. The spectra all show a simple rotational structure, characteristic of R-R transitions. A full analysis has been performed of the previously unobserved 4f(v = 0) → F²Δ(v = 0) band at 1.71 μm. The band shows a peculiar structure, characteristic of Hund's Case (d) behaviour for one of the states. The relative branch intensities are calculated from first principles, and the agreement with the observed spectrum is excellent. This work shows the potential of interferometers for studying excited electronic states of simple molecules at high resolution.     

The υ1 fundamental bands of trans- and cis-DONO studied by high-resolution Fourier-transform spectroscopy

The absorption spectrum of deuterated nitrous acid DONO in the region from 2350 to 3000 cm⁻¹ has been recorded at a resolution of 0.003 cm⁻¹ using a Fourier-transform spectrometer. For the first time, 1366 a- and b-type transitions in the υ₁ fundamental band of trans-DONO and 741 b-type transitions in the υ₁ fundamental band of cis-DONO have been assigned. Rotational and centrifugal distortion constants up to sextic order were determined for the v₁ = 1 states of trans- and cis-DONO using non-linear least-squares calculations. Synthetic spectra calculated using the new rovibrational constants obtained for both species reproduce the observed spectra very well. In addition, the infrared transitions of this study were used, together with previously published pure rotational transitions, to determine improved rotational and centrifugal distortion constants of the ground states of trans- and cis-DONO.     

Microwave spectra of thionyl fluoride in vibrationally excited states

The microwave spectrum has been observed and rotational constants obtained for the v₄ = 1 and v₆ = 1 vibrationally excited states of thionyl fluoride. The perturbation of the C rotational constant is explained in terms of a Coriolis resonance between these levels.     

The Stimulated Raman Spectrum of Cyanogen

The Raman spectrum of cyanogen¹²C₂¹⁴N₂has been investigated at nearly Doppler resolution by means of the Stimulated Raman technique. The regions around theQbranches of the ν₁(2330 cm⁻¹) and ν₂(845 cm⁻¹) vibrations have been recorded. Besides the fundamentals, hot bands arising fromv₅= 1,v₅= 2, andv₄= 1 have been observed. The spectra have been analyzed, and rotational constants for the excited states have been obtained. Computer simulations of the Raman contours have been carried out as a test of the assignments.     

The perpendicular band ν14 of benzene near 10 μm

The perpendicular band of the E_1u vibration ν₁₄ of C₆H₆, with band origin at 1038.2670 cm^?1, was measured on a Bomem high-resolution Fourier transform spectrometer with a 246-cm optical path difference. The spectrum was deconvolved to an effective linewidth of ～0.002 cm^?1. A total of 135 subbands have been assigned in the ν₁₄ band. The band was found to be remarkably free of perturbations by other states. A Hamiltonian matrix of order 2, including merely the rotational l-type resonances between the ν₁₄⁺(J, K) and ν₁₄^?(J, K ? 2) levels, was used for the treatment of the upper states of this band. A set of accurate spectroscopic constants was obtained, which reproduces a total of 3258 measured lines with an over-all standard deviation of 0.0006 cm^?1.     

Spectroscopic constants of the ground and lower vibrational states of CH2BrF: A combined high resolution infrared and microwave study

The enriched ⁸¹Br isotopic species of bromofluoromethane has been investigated in the infrared and microwave regions. The rovibrational spectrum of the ν₅ fundamental has been studied by high resolution FTIR spectroscopy, while the rotational spectra of the ground and v₆ = 1 states have been observed by means of microwave spectroscopy. More than 2700 transitions have been assigned in the ν₅ band and the analysis of the rovibrational structure reveals a first-order c-type Coriolis resonance with the v₆ = 2 state. The present study improves the ground state constants available in the literature and enables the determination of further centrifugal distortion parameters together with the full bromine quadrupole coupling tensor. A set of spectroscopic parameters up to the sextic distortion terms for the vibrational excited states has been accurately evaluated for the first time.     

Conformation and dipole moment of tetrahydropyran-4-one by microwave spectroscopy

The microwave spectrum of tetrahydropyran-4-one has been studied in the frequency region 18 to 40 GHz. The rotational constants for the ground state and nine vibrationally excited states have been derived by fitting a-type R-branch transitions. The rotational constants for the ground state are (in MHz) A = 4566.882 ± 0.033, B = 2538.316 ± 0.003, C = 1805.878 ± 0.004. From information obtained from the gas-phase far-infrared spectrum and relative intensity measurements, these excited states are estimated to be ～ 100 cm^?1 above the ground state for the first excited state of the ring-bending and ～ 185 cm^?1 for the first excited state of the ring-twisting mode. Stark displacement measurements were made for several transitions and the dipole moment components determined by least-squares fitting of the displacements: (in Debye) |μ_a| = 1.693 (0.001), |μ_b| = 0.0, |μ_c| = 0.300 (0.013) yielding a total dipole moment μ_tot = 1.720 (0.003). A model calculation to reproduce the rotational parameters indicates that the data are consistent with the chair conformation.     

High-resolution infrared spectrum and analysis of the ν1 band of CF337Cl

The rotational structure of CF₃³⁷Cl ν₁ band has been investigated using spectra of trifluorochloromethane in natural isotopic abundance, recorded with a tunable diode laser spectrometer. The spectra analyzed have been obtained by keeping the sample at low temperature (～200 K) to minimize the strong interference arising from “hot” band transitions. The K structure of many P(J) and R(J) multiplets has been resolved and positively identified: the maximum J value reached in the P and R branches was 38 and 40, respectively. About 650 unblended lines have been used for the least-squares fit to the energy expression including the quartic centrifugal distortion coefficients. Molecular constants for the ν₁ band of CF₃³⁷Cl have been derived. A weak perturbation affecting the rotational levels with K = 18 and J′ ≥ 36 has also been observed.     

The millimeter wave spectrum of phosphorus oxychloride

Millimeter wave rotational spectra of phosphorus oxychloride (OPCl₃) in the ground and excited vibrational states have been recorded and analyzed. The v₅ = 1 and v₆ = 1 state spectra show large splittings due to l resonance and the effect of the 2, -1 term r_t. Coriolis constants have been obtained for the two lowest degenerate states. The spectra of the asymmetric top species OP³⁵Cl₂³⁷Cl have been analyzed and centrifugal distortion constants obtained. These have been used to determine the harmonic force field of the molecule.     

SiH4紫外多光子电离光谱的转动分析

本工作用激光扫描步长6×10^-4nm观测了SiH₄多光子电离光谱中363.52nm附近的精细结构。SiH₄被三光子共振激发后,作为略不对称陀螺处理。大多数转动谱线被论证为v₂振动垂直谱带的一个Q支,并推算出激发态转动常数B＇=3.04±0.01cm^-1。 关键词：     

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.     

Hyperdeformation and clusterization in the actinide region

The ²³³U(d,pf)²³⁴U, and the ²³⁵U(d,pf)²³⁶U reactions have been studied with high energy resolution. The observed fission resonances were described as members of rotational bands with rotational parameters characteristic of hyperdeformed nuclear shapes. Information on the K values of the bands and for the J values of the band members has been obtained from fission fragment angular distribution measurements. The level density of the most strongly excited states has been compared to the prediction of the back-shifted Fermi-gas formula and the energy of the ground state in the third minimum has been estimated for ²³⁴U. The fission fragment mass distribution of the hyperdeformed states in ²³⁶U has also been measured. The width of the mass distribution, coincident with the hyperdeformed bands, is significantly smaller than the ones obtained in coincidence with background regions below and above the resonances, which suggests a pear-shaped di-nuclear configuration of ²³⁶U in the third well of the potential barrier.     

Collective and intrinsic structures in 183W

The structure of ¹⁸³W has been studied by employing the ¹⁷⁶Yb(¹⁴C,α3n) reaction at 68 MeV. Five previously known rotational structure with one-quasiparticle configurations have been extended to higher spin states, and five new rotational bands with three- and five-quasiparticle configurations and a γ-vibration of a one-quasiparticle structure have been newly identified. In the ν7/2⁻[503] and ν11/2⁺[615] rotational structures, a signal of an admixture of an octupole-vibrational structure has been observed in their in-band B(M1)/B(E2) ratios and g_K factors. In the K^π=19⁻ rotational band, a Coriolis effect on the ν1/2⁻[510] neutron has been identified. In all, 17 K-forbidden transitions have been observed. Energies of intrinsic states below 4 MeV have been calculated based on the Blocked BCS theory, and they are used in support of the configuration assignments.