Observed Energy Levels Research Articles

High spin states in 71Ga * *Supported by the National Natural Science Foundation of China (U1932209, 11975315, U1867210, 11905134), the Leading Innovation Project under Grant (LC192209000701, LC202309000201), the Continuous Basic Scientific Research Project (BJ20002501, WDJC-2019-13), China National Nuclear Corporation (FA18000201)

Excited states in the odd-A nucleus 71Ga have been studied via the 70Zn(7Li, )71Ga fusion-evaporation reaction with incident beam energies of 30 and 35 MeV. The level scheme is established up to spin = (29/2+) and an excitation energy 6.6 MeV. A previously known sequence built on the 9/2+ state is extended as a novel rotational band originating from the alignment. Furthermore, a negative-parity sequence is also reported. The observed energy levels of 71Ga have been interpreted in the framework of the nuclear shell model (SM).

Intra- and inter-configurational electronic transitions of Ce3+-doped Y2SiO5 : Spectroscopy and crystal field analysis

We report on an interpretation of the 4 f → 5 d absorption and fluorescence spectra as well as the previously un-reported intra-4 f transitions between the Stark levels of the 2 F 5/2 and 2 F 7/2 multiplets of the single seven-fold coordinated, C 1 symmetry site for Ce 3+ in Y 2 SiO 5 . Further, We also give the corresponding crystal-field parameters determined by fitting to the observed energy level data and the ground state Zeeman g tensor obtained from previously reported electron paramagnetic resonance (EPR) measurements. Finally we present a temperature-dependent analysis of the linewidth and position of the 4 f → 4 f absorption lines. • High-resolution infrared absorption measurements for Y 2 SiO 5 :Ce 3+ . • UV fluorescence and absorption spectroscopy of Y 2 SiO 5 :Ce 3+ . • Crystal-field analysis of 4f 1 and 4f5d 1 electronic energy levels of Y 2 SiO 5 :Ce 3+ . • Temperature-dependent linewidth and line shift analysis of Y 2 SiO 5 :Ce 3+ .

A spectroscopic model for the low-lying electronic states of NO.

The rovibronic structure of A2Σ+, B2Π, and C2Π states of nitric oxide (NO) is studied with the aim of producing comprehensive line lists for its near ultraviolet spectrum. Empirical energy levels for the three electronic states are determined using a combination of the empirical measured active rotation-vibration energy level (MARVEL) procedure and ab initio calculations, and the available experimental data are critically evaluated. Ab initio methods that deal simultaneously with the Rydberg-like A2Σ+ and C2Π and the valence B2Π state are tested. Methods of modeling the sharp avoided crossing between the B2Π and C2Π states are tested. A rovibronic Hamiltonian matrix is constructed using the variational nuclear motion program Duo whose eigenvalues are fitted to the MARVEL. The matrix also includes coupling terms obtained from the refinement of the ab initio potential energy and spin-orbit coupling curves. Calculated and observed energy levels agree well with each other, validating the applicability of our method and providing a useful model for this open shell system.

Quantum Ising Hamiltonian Programming in Trio, Quartet, and Sextet Qubit Systems

Rydberg-atom quantum simulators are of keen interest because of their possibilities towards high-dimensional qubit architectures. Here we report three-dimensional conformation spectra of quantum-Ising Hamiltonian systems with programmed qubit connections. With a Rydberg-atom quantum simulator, various connected graphs, in which vertices and edges represent atoms and blockaded couplings, respectively, are constructed in two or three-dimensional space and their eigenenergies are probed during their topological transformations. Star, complete, cyclic, and diamond graphs, and their geometric intermediates, are tested for four atoms and antiprism structures for six atoms. Spectroscopic resolution (dE/E) less than 10% is achieved and the observed energy level shifts and merges through structural transformations are in good agreement with the model few-body quantum-Ising Hamiltonian.

The W2020 Database of Validated Rovibrational Experimental Transitions and Empirical Energy Levels of Water Isotopologues. II. H217O and H218O with an Update to H216O

The W2020 database of validated experimental transitions and accurate empirical energy levels of water isotopologues, introduced in the work of Furtenbacher et al. [J. Phys. Chem. Ref. Data 49, 033101 (2020)], is updated for H216O and newly populated with data for H217O and H218O. The H217O/H218O spectroscopic data utilized in this study are collected from 65/87 sources, with the sources arranged into 76/99 segments, and the data in these segments yield 27 045/66 166 (mostly measured) rovibrational transitions and 5278/6865 empirical energy levels with appropriate uncertainties. Treatment and validation of the collated transitions of H216O, H217O, and H218O utilized the latest, XML-based version of the MARVEL (Measured Active Rotational-Vibrational Energy Levels) protocol and code, called xMARVEL. The empirical rovibrational energy levels of H217O and H218O form a complete set through 3204 cm−1 and 4031 cm−1, respectively. Vibrational band origins are reported for 37 and 52 states of H217O and H218O, respectively. The spectroscopic data of this study extend and improve the data collated by an International Union of Pure and Applied Chemistry Task Group in 2010 [J. Tennyson et al., J. Quant. Spectrosc. Radiat. Transfer 110, 2160 (2010)] as well as those reported in the HITRAN2016 information system. Following a minor but significant update to the W2020-H216O dataset, the joint analysis of the rovibrational levels for the series H216O, H217O, and H218O facilitated development of a consistent set of labels among these three water isotopologues and the provision of accurate predictions of yet to be observed energy levels for the minor isotopologues using the combination of xMARVEL results and accurate variational nuclear-motion calculations. To this end, 9925/8409 pseudo-experimental levels have been derived for H217O/H218O, significantly improving the coverage of accurate lines for these two minor water isotopologues up to the visible region. The W2020 database now contains almost all of the transitions, apart from those of HD16O, required for a successful spectroscopic modeling of atmospheric water vapor.

Clustering energy calculation in light alpha-conjugated nuclei

In this paper, clustering energy was investigated in light alpha-conjugate nuclei considering cluster–cluster interaction instead of nucleon–nucleon interaction and using the phenomenological non-microscopic method. The observed energy levels were calculated from the rotational band of 8Be, 12C, and 16O isotopes. The results showed that these isotopes, in their cluster state, have a non-spherical structure.

Thermochemical spin‐orbit corrections for platinum cation (Pt+)

AbstractIn quantum thermochemistry, many atoms require spin‐orbit corrections to compensate for the lack of spin‐orbit coupling in most calculations. When terms or configurations are strongly mixed, as they are in Pt+, naïve averaging of experimental data produces erroneous corrections. Here, spin‐orbit calculations provide the composition of observed energy levels in LS (Russell‐Saunders) terms. The compositional data are combined with the experimental energy levels to obtain averaged term energies for Pt+, including the ground‐term spin‐orbit correction. For ground‐state Pt+, a correction of (−4251 ± 136) cm−1 or (−50.8 ± 1.6) kJ mol−1 is recommended. The recommended value for the 2D‐4F excitation energy, which represents the nominal 5d‐6s promotion energy, is (7112 ± 225) cm−1. For anionic Pt−, simple J‐averaging is appropriate, and the ground‐state spin‐orbit correction is (−3896.4 ± 0.2) cm−1 or (−46.611 ± 0.002) kJ mol−1.

Coriolis Coupling in the Continuum

In 1956 A. Kerman explained the observed energy levels of the lowest K = 1/2 and K = 3/2 bands in 183W as resulting from rotational perturbations due to the effects of the Coriolis force. Following from that seminal paper, in this work we consider Kerman’s problem when one of the Nilsson single-particle levels involved is a resonant state. This is the simplest model of Coriolis mixing that allows for analytical expressions derived in first-order perturbation theory, without losing the main physical ingredients of the continuum effects. We present results for the perturbed solution of the ground state band energies as a function of the state width, which suggest a general behavior of both increased moment of inertia and staggering.

Revised and extended analysis of doubly ionized bismuth: Bi III

The third spectrum of bismuth (Bi III) with its ground configuration 5d106s26p has been investigated in the wavelength region 278–2000 Å using spectrograms recorded on a 3-m normal incidence vacuum spectrograph. The observed spectrum was interpreted using semi-empirical calculations with Cowan's code in the framework of the quasi-Relativistic Hartree-Fock method. Analyses made by previous investigators on one and three-electron systems were checked thoroughly, while the tentative identification of the 2S1/2 level of the 5d106s6p2 configuration is confirmed. For the first time we had investigated the 6p3, 6s6p6d and 6s6p7s odd configurations based on the identification of 99 spectral lines. In total, 67 energy levels are now established in the 5d10[6s2np (n = 6–8) + 6s2nf (n = 5–7) + 6s2nh (n = 6–7)], 6s6p2 and 5d96s26p2 configurations, among which 23 energy levels were newly located. The least squares parametric fitting calculations were performed to interpret the final results of the analysis. Optimization of the observed energy levels was carried out with the computer program LOPT. The ionization energy was found to be 206,242.0 ± 1.4 cm−1 (25.5708±0.0002 eV).

High-resolution angle-resolved photoemission study of oxygen adsorbed Fe/MgO(001)**Present address: Synchrotron Radiation Research Center, National Institutes for Quantum and Radiological Science and Technology, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan

We have investigated the electronic states of clean Fe(001) and oxygen adsorbed Fe(001)–p(1 × 1)-O films epitaxially grown on MgO(001) substrates by means of polarization-dependent angle-resolved photoemission spectroscopy (ARPES) and extensive density-functional theory (DFT) calculations. The observed Fermi surfaces and band dispersions of pure Fe near the Fermi level were modified upon oxygen adsorption. By the detailed comparison of ARPES and DFT results of the oxygen adsorbed Fe surface, we have clarified the orbital-dependent p–d hybridization in the topmost and second Fe layers. Furthermore, the observed energy levels and Fermi wave numbers for the oxygen adsorbed Fe surface were deviated from the DFT calculations depending on the orbital characters and momentum directions, indicating an anisotropic interplay of the electron correlation and p–d hybridization effects in the surface region.

Investigations of crystal-field energy levels and microscopic spin-Hamiltonian parameters of Mn4+ ions in pyrochlore hosts Y2Ti2O7 and Y2Sn2O7

We investigate the crystal-field energy levels and the microscopic origin of spin-Hamiltonian parameters (SHPs), i.e. g-factors and zero-field splitting parameter D, for the ground state 4A2g(4F) of Mn4+ impurity ions at trigonal sites in host pyrochlores, Y2Ti2O7 and Y2Sn2O7. The total Hamiltonian includes the electrostatic and crystal-field (CF) Hamiltonians, and the magnetic interactions, i.e. spin-orbit, spin-spin, spin-other-orbit, and orbit-orbit couplings. The calculations are performed under the complete diagonalization method and microscopic spin-Hamiltonian (CDM/MSH) program. The calculated CF levels agree reasonably well with the observed energy levels for Mn4+ ions in these compounds. The SHPs are evaluated with the CDM/MSH wave functions as well as by a perturbation loop theory method (PLTM). The g-factors of Mn4+ in Y2Ti2O7 and Y2Sn2O7 using PLTM are close to those evaluated by CDM, while the PLTM value of D shows appreciable difference with the CDM value. This evidences that the g-factors depend predominately on the lower states, while the higher energy states significantly affect the D value. The contributions of spin-spin, spin-other-orbit, and orbit-orbit couplings to the CF energy levels and the SHPs are discussed.

Improving the efficiency of perovskite light emitting diode using polyvinylpyrrolidone as an interlayer

A few nanometer-thick polyvinylpyrrolidone (PVP) interlayer between PEDOT:PSS anode and active layer was introduced in a perovskite light-emitting diode (PeLED) in conjunction with nanocrystal pinning (NCP) process. The device with the PVP interlayer exhibited dramatic improvements in performance resulting in current efficiency of 20.89 cd A-1, external quantum efficiency (EQE) of 5.4%, the luminance of 39,023 cd m−2, and FWHM of 18 nm, despite the fact that some degree of intermixing of the layers was expected because identical solvent was used for all three layers (PEDOT:PSS, PVP, and perovskite). The interface between PVP and perovskite layer was investigated by using x-ray and ultraviolet photoelectron spectroscopy (XPS and UPS) sputter depth profiling with Ar gas cluster ion beam. Although obtaining a clear interface in XPS depth profile data was not possible because of partial interlayer mixing and the thinness of the PVP layer, an obvious difference across the interface was extracted in the UPS data. The observed energy level diagram was consistent with the characteristic of hole-only device (HOD) in which charge injection from PEDOT:PSS anode to the perovskite layer was suppressed due to the PVP layer.

Thermochemical spin‐orbit corrections for atomic platinum (Pt)

AbstractIn quantum chemistry calculations of molecular dissociation or atomization, the energies of many atoms require spin‐orbit corrections (SOCs). This is to compensate for the lack of spin‐orbit coupling in most calculations. Values for the corrections are normally derived from experimental atomic energy levels and their assignments to LS (Russell‐Saunders) terms. However, this procedure produces erroneous values when terms are strongly mixed, as they are in Pt. Spin‐orbit configuration interaction provides the LS‐term composition of observed energy levels. Such data are used here to obtain SOCs for valence term energies of Pt. For the ground term (3D), a correction of −3948 ± 153 cm−1 is recommended.

Extended atomic structure calculations for energy levels and radiative data of Xe XLIII

We report an extensive and elaborate theoretical study of atomic data for Xe XLIII. We have calculated energies for the lowest 141 fin. structure levels by using Multi-Configuration Dirac Fock (MCDF) method. We have also considered Quantum Electrodynamics (QED) and Breit corrections in our calculations. We have presented the radiative data for electric dipole (E1) transitions among lowest 141 levels. We have made comparisons of our calculated excitation energies and EUV (Extreme Ultraviolet) transition wavelengths with the theoretically computed and experimentally observed energy levels and wavelengths at Electron Beam Ion Trap (EBIT) and a good agreement is achieved. We have also computed energy levels by performing similar relativistic distorted wave calculations using Flexible Atomic Code (FAC). Additionally, we have provided new atomic data for Xe XLIII which are not published elsewhere in the literature. We believe that our results may be beneficial in fusion plasma research and detection and investigation of EUV and Soft X-ray (SXR) spectral lines.

Highly excited vibrational levels of methane up to 10 300 cm−1: Comparative study of variational methods

In this work, we report calculated vibrational energy levels of the methane molecule up to 10 300 cm-1. Two potential energy surfaces constructed in quite different coordinate systems with different analytical representations are employed in order to evaluate the uncertainty of vibrational predictions. To calculate methane energy levels, we used two independent techniques of the variational method. One method uses an exact kinetic energy operator in internal curvilinear coordinates. Another one uses an expansion of Eckart-Watson nuclear motion Hamiltonian in rectilinear normal coordinates. In the Icosad range (up to five vibrational quanta bands-below 7800 cm-1), the RMS standard deviations between calculated and observed energy levels were 0.22 cm-1 and 0.41 cm-1 for these two quite different approaches. For experimentally well-known 3v3 sub-levels, the calculation accuracy is estimated to be ∼1 cm-1. In the Triacontad range (7660-9188 cm-1), the average error of the calculation is about 0.5 cm-1. The accuracy and convergence issues for higher energy ranges are discussed.

Deciphering the Microstructure and Energy-Level Splitting of Tm3+-Doped Yttrium Aluminum Garnet.

Thulium-doped yttrium aluminum garnet (Tm:YAG) is an important solid-state laser crystal. The energy-level splitting within it is still an unresolved problem. Here, we perform a theoretical study on the microstructure of Tm3+-doped YAG using the CALYPSO structure search method in conjunction with first-principles calculations. The calculated results show that the 4.16% doping concentration of Tm3+ impurity causes an obvious structural distortion of YAG crystal, forming an orthorhombic phase in C222 symmetry. On the basis of our developed WEPMD method, we obtain a new and complete set of free-ion and crystal field parameters by a good fit (with proper irreducible representations) to 69 observed energy levels and determine the exact energy-level splitting of Tm3+ in YAG. The calculated Stark levels and electric dipole transitions are in excellent agreement with the measured data and similar theoretical calculations. Some promising emission lines between 3F3, 3F2, 1D2, and 1I6 states are presented. These findings offer fundamental insights and practical tools for further exploration of the structural and electronic properties of other transition-metal-doped YAG crystal.

Spectroscopic study of EUV and SXR transitions of Cs XXV

We report an extensive and elaborate theoretical study of atomic data for Cs XXV by using multi-configuration Dirac–Fock method and calculated energy levels for the lowest 110 fine structure levels. We have presented the radiative data for electric and magnetic dipole (E1, M1) and quadrupole (E2, M2) transitions among lowest 110 levels. We have made comparisons of our calculated excitation energies with theoretically calculated and experimentally observed energy levels. We have studied the effect of correlation by introducing more configurations in our calculations. We have also computed energy levels by performing similar relativistic distorted wave calculations using Flexible Atomic Code. Additionally, we have also provided new atomic data for Cs XXV and identified extreme ultraviolet and soft X-ray spectral lines with gA spectra for E1 and M2 transitions, which are not published elsewhere in the literature. We believe that our results may be beneficial in fusion plasma research and applications.

Revised and extended analysis of the third spectrum of silver: Ag III

The spectrum of doubly ionized silver (Ag III) having the ground configuration 4p64d9 has been investigated. The silver spectra were recorded on a 3-m normal incidence vacuum spectrograph at St. Francis Xavier University, Antigonish (Canada) using a triggered spark source. Theoretical predictions based on the Hartree–Fock method were made using superposition of interacting configurations and relativistic corrections. For proper interpretation of configuration interaction, the configurations 4p6[4d9, 4d8ns (n=5–9), 4d8nd (n = 5–9), 4d8ng (n=5–7), 4d75s2 and 4d75p2] and 4p54d10, 4p6[4d8np (n=5–7), 4d8nf (n = 4–6), 4d8nh (n = 6–7), 4d75s5p and 4d75s4f] were incorporated in the even and odd parity systems, respectively. The previous analyses were checked thoroughly; five levels of 4d85p were revised and two configurations, viz., 4d85d and 4d86s have been investigated for the first time. A total of 124 energy levels were established belonging to the configurations 4p6[4d9+4d8(5s + 6s + 5p + 5d)], among which 64 levels of 4p64d8(5d + 6s) were newly established. Least squares fitting parametric calculations were carried out to interpret the observed energy level structure. The observed energy levels were optimized to fit the measured wavelengths.

Rotational band on a three-quasineutron isomer in Xe127

Excited states in $^{127}\mathrm{Xe}$ were populated via $^{122}\mathrm{Sn}{(}^{9}\text{Be},4n\ensuremath{\gamma})$ fusion-evaporation reaction at ${E}_{\text{beam}}=48$ MeV. A rotational band above an isomeric state at 2730.3 keV has been established. ${J}^{\ensuremath{\pi}}=23/{2}^{+}$ has been assigned unambiguously to the bandhead. Structural features, configuration, and reduced hindrance factor per degree of $K$-forbiddenness (${f}_{\ensuremath{\nu}}$) have been discussed in the context of neighboring nuclei. Half-lives of $7/{2}^{+}$ (${t}_{1/2}=37\ifmmode\pm\else\textpm\fi{}1$ ns) and $23/{2}^{+}$ (${t}_{1/2}=28\ifmmode\pm\else\textpm\fi{}1$ ns) isomeric states have also been estimated and found to be consistent with the earlier reported values. The experimentally observed energy levels of the rotational band have been reproduced successfully by theoretical calculations carried out using the modified particle rotor model (MPRM) with ${\ensuremath{\beta}}_{2}\ensuremath{\sim}0.22$ and ${15}^{\ensuremath{\circ}}\ensuremath{\lesssim}\ensuremath{\gamma}\ensuremath{\lesssim}{22}^{\ensuremath{\circ}}$.

IDEN2—A program for visual identification of spectral lines and energy levels in optical spectra of atoms and simple molecules

The article describes a Java program that can be used in a user-friendly way to visually identify spectral lines observed in complex spectra with theoretically predicted transitions between atomic or molecular energy levels. The program arranges various information about spectral lines and energy levels in such a way that line identification and determination of positions of experimentally observed energy levels become much easier tasks that can be solved fast and efficiently. Program summaryProgram title: IDEN2Program Files doi: http://dx.doi.org/10.17632/mwr2tk84sw.1Licensing provisions: GPLv3Programming language: Java v.1.8Nature of problem: Line identification problem in atomic and molecular spectra that have a limited number of previously known low-excited energy levels and a large number of unidentified spectral lines (emission or absorption). The line identification consists of finding the lower and upper energy levels of transitions corresponding to each observed spectral line.Solution method: For each energy level (experimentally known or unknown), the list of observed spectral lines is displayed on a wavenumber scale as an image. This image is repeated with certain vertical shifts in several columns corresponding to other levels connected with the investigated one by theoretically predicted transitions. In each such column, the image of the line spectrum is shifted by the value corresponding to the energy of the connecting level. Then the problem of location of an unknown level is reduced to scrolling the screen until several spectral lines in different columns align along the same horizontal line. Various gadgets provide complete information about all pertinent entities, such as the level identities, wavelengths, observed and calculated intensities.Additional comments including restrictions and unusual features: A practical limitation on the size of the problem is imposed by the available RAM, which is typically sufficient to treat spectra with up to 100 000 spectral lines and 10 000 energy levels. The visual appearance of all gadgets, including font sizes, colors, and window sizes and positions, is completely customizable. An extensive Help system and User Guide are included.