High-spin states of rotational bands built upon νi13/2 in 166Lu

High-Spin states of odd-odd ¹⁶⁶Lu were populated using the ¹³⁹La(³⁰Si,3nγ)¹⁶⁶Lu at a beam energy of 120 MeV. Twelve new γ-rays were placed on top of the previously known two rotational bands built upon πg _7/2⊗νi _13/2 and πh _11/2⊗νi _13/2. Extending high-spin states up to 21⁺ and 25⁻ for each band, we have observed the onset of band crossing near ħω _c ≈ 0.35 MeV. The band crossing frequency of the yrast πh _11/2⊗νi _13/2 band is consistent with the neutron BC band crossing observed in lighter odd-odd Lu isotopes.     

Multiple bands: A key to high-temperature superconductivity in iron arsenides?

In the framework of four-band model of superconductivity in iron arsenides proposed by Barzykin and Gor’kov we analyze the gap ratios on hole—like and electron—like Fermi—surface cylinders. It is shown that experimentally observed (ARPES) gap ratios can be obtained only within rather strict limits on the values of pairing coupling constants. The difference of T _c values in 1111 and 122 systems is reasonably explained by the relative values of partial densities of states. The multiple bands electronic structure of these systems leads to a significant enhancement of effective pairing coupling constant determining T _c , so that high enough T _c values can be achieved even for the case of rather small intraband and interband pairing interactions. The article is published in the original.     

Does the Helium Trimer Have Bound Rotational States?

For the ⁴He₃ trimer, calculations predict two bound states with total angular momentum J = 0. This result gave rise to speculations that also bound states with J ≠ 0 might exist. Using the symmetry-adapted version of the adiabatic hyperradial approach (SAHA) we search for such bound states. Our conclusion is that ⁴He₃ has no bound rotationally excited states. This revised version was published online in August 2006 with corrections to the Cover Date.     

Rotational Rydberg states of polar molecules: Hund’s classification and Zeeman effect

The rotational Rydberg states of polar molecules, which arise as a result of the interaction of a Rydberg electron with core rotations, are considered. A large number of angular momenta in the core-electron system lead to a considerably greater number of possible coupling schemes of these momenta compared to the number of schemes determined by the classical five Hund’s cases for lower excited electron states of molecules. As a result of such detailed Hund’s classification, more than 30 different coupling schemes (Hund’s subcases) are constructed for rotational Rydberg states of molecules. The conditions of their realization are indicated in terms of the relative quantities of intramolecular interactions, for which analytical estimates are presented. For a large number of subcases, analytical expressions for the molecular matrix elements are found. These expressions can be useful in classification of the experimental spectra of highly excited molecules. As an application, for each of the subcases considered, analytical expressions are given, which describe the linear Zeeman effect and the Paschen-Back effect.     

Optical homogeneity analysis of Hg1−xCdxTe epitaxial layers: How to circumvent the influence of impurity absorption bands?

Optical absorption and photoluminescence spectroscopies are standard tools for analysis of HgHg_1−xCd_xTe epitaxial layers in terms of homogeneity of the mole-fraction (x). For technological relevant layer thicknesses of ∼10 μm, both techniques may show dissimilar results, in particular if doped layers are investigated. This is due to defect levels, which impact to the results obtained by both techniques in different ways. We systematically investigate this behavior by analyzing two sets of HgCdTe layers, one set intrinsically doped by Hg-vacancies, the other extrinsically doped by arsenic (As). A model is outlined and applied to the experimental results, which consistently explains even non-monotonous temperature-shifts of the spectra. Eventually, guidelines for optical homogeneity tests are given. While transmission measurements are most reliable, when carried out at low temperature, where the defect level are frozen out, photoluminescence provides best results at ambient temperature, where band-states are increasingly populated. Both approaches help to reveal intrinsic material properties.     

Rotational and vibrational analysis of bands of the f1Δ-a1Δ system of titanium oxide

Five new bands of the f¹Δ-a¹Δ TiO system have been observed in emission between 17774.0 cm^?1 and 19801.0 cm^?1. Rotational and vibrational analyses of the 0-1, 1-0, 1-2, 2-1, and 1-1 bands, as well as a reanalysis of the 0-0 band, yielded the following molecular constants (cm^?1):

     

8.

Emission bands of AIH (X1Σ+): The 2-0 sequence     

《Journal of Molecular Spectroscopy》1987,125(1):115-121

Seven bands of the 2-0 sequence of AlH in its X¹Σ⁺ ground state have been observed in emission from a carbon furnace and recorded with a Bomem interferometer. Improved values for the molecular constants have been obtained. The principal constants are B_e = 6.3937(4), α₃ = 0.1868(3), 10⁴D_e = 3.683(10), ω_e = 1682.43, and ω_eχ_e = 29.11 cm⁻¹, where the error limits are 3σ. Possibilities for observing AlH in astrophysical sources are discussed.     

9.

High resolution absorption spectrum of CO2between 1750 and 2000 Å. 2. Rotational analysis of two parallel-type bands assigned to the lowest electronic transition 13B2← 1     

Claudina Cossart-Magos  Fran?oise Launay  James E. Parkin 《Molecular physics》2013,111(5):629-641

     

10.

Temperature dependence of the Mössbauer effect on the semiconductors Pb0.78Sn0.22Te and Pb0.80Sn0.20Te:In     

T. Ragimova  W.A. Pacheco Serrano  A. Abras 《Hyperfine Interactions》1999,122(1-2):185-188

Crystals of the semiconductors Pb_0.78Sn_0.22Te and Pb_0.80Sn_0.20Te:In were grown by Bridgman method, and investigated by Mössbauer spectroscopy and X-ray diffraction. Mössbauer spectra were taken at temperatures between 80 and 300 K. The absence of the quadrupole splitting shows a cubic symmetry of the environment for the tin atom, which is in accordance with X-ray data. The temperature dependence of the spectral area is discussed and the Debye temperature is estimated.     

11.

Ground-state, β and K = 11/2? γ bands in 163, 165Er     

M. J. Ermamatov  P. C. Srivastava  P. R. Fraser  P. Stránsky 《The European Physical Journal A - Hadrons and Nuclei》2012,48(9):1-7

Neutron production by stopping 55 MeV deuterons in thick carbon and heavy-water targets has been measured by the activation method. The geometry was close to the one defined for the SPIRAL2 uranium-carbide target in the initial phase. A comparative method for obtaining the neutron flux has been used and is presented in detail. The neutron flux generated by 55 MeV deuterons on carbon is 2.3 times the flux at the deuteron energy of 40 MeV. The flux further increases by a factor 1.4 when using a heavy-water target. These results are discussed in the context of an energy upgrade of the SPIRAL2 driver accelerator.     

12.

The ν1 and ν3 bands of 16O3: Line positions and intensities     

《Journal of Molecular Spectroscopy》1987,124(1):209-217

Using 0.005 cm⁻¹ resolution Fourier transform spectra of samples of ozone, the ν₁ and ν₃ bands of ¹⁶O₃ have been reanalyzed to obtain accurate line positions and an extended set of upper state rotational levels (J up to 69, K_a up to 20). Combined with the available microwave data, these upper state rotational levels were satisfactorily fitted using a Hamiltonian which takes explicitly into account the strong Coriolis interaction affecting the rotational levels of these two interacting states. In addition, 350 relative line intensities were measured from which the rotational expansions of the transition moment operators for the ν₁ and ν₃ states have been deduced. Finally, a complete listing of line positions, intensities, and lower state energies of the ν₁ and ν₃ bands of ¹⁶O₃ has been generated.     

13.

Can multiband coupling effects due to remote bands cause significant normal-incidence absorption inn-type direct-gap semiconductor quantum wells?     

《Superlattices and Microstructures》1998,24(3):209-214

Surprisingly, several experiments have reported that normal-incidence light absorption due to inter-conduction-subband transitions in direct-gap semiconductor quantum wells is as strong as in-plane-incidence absorption. In contrast to other models, a recent theoretical study claimed that a 14-bandk  pmodel including multiband coupling terms due toremote-conduction bandsis able to explain the experimental results. In this work, a concise formulation extends the model beyond 14 bands. Nevertheless, after rederiving the optical transition matrix elements, this analysis clearly shows that the oscillator strength for the in-plane polarized optical intersubband transition due to the multiband coupling effects is much smaller than the oscillator strength for the normal-to-plane polarized optical intersubband transition. These results indicate that the multiband coupling effects due to remote-conduction bands cannot cause a sufficient in-plane polarized optical intersubband transition to produce the observed normal-incidence absorption in the desirablen-type III–V compound semiconductor quantum wells.     

14.

Photon scattering off 52Cr: Two-phonon E1 strength at the N = 28 shell closure?     

《Nuclear Physics A》1998,636(2):139-155

     

15.

Pre-exponential factor for the crystallization of glassy Se80Te20 and Se75Te20M5 alloys: applicability of Meyer–Neldel rule     

Shipra Saraswat  S.S.S. Kushwaha  A. Kumar 《Phase Transitions》2013,86(5):357-365

The Meyer–Neldel rule or MN rule (also known as compensation effect) is an empirical law known since 1937. This rule is observed in wide range of phenomena in physics, chemistry, biology and electronics. Many activated phenomena, including solid state diffusion in crystals and polymers, dielectric relaxation, conduction and thermally stimulated processes in polymers, and electronic conduction in amorphous semiconductors obey the MN rule. In the present article, we report the MN rule in the non-isothermal crystallization in glassy Se₈₀Te₂₀ and Se₇₅Te₂₀M₅ (M = Ag, Cd, In, Sb) alloys. We have observed MN rule between pre-exponential factor K _o and activation energy of crystallization E _c in the present case for thermally activated non-isothermal crystallization.     

16.

Personal recollections of 52 years of M?ssbauer spectroscopy research     

Israel Nowik 《Hyperfine Interactions》2012,204(1-3):57-64

The history of the scientific developments of the M?ssbauer effect, through 52 years, is discussed in terms of personal observations and participation.     

17.

Using simple elastic bands to explain quantum mechanics: a conceptual review of two of Aerts’ machine-models     

Massimiliano Sassoli de Bianchi 《Central European Journal of Physics》2013,11(2):147-161

     

18.

Amorphous Ge??Te??: density functional, high-energy x-ray and neutron diffraction study     

Kalikka J  Akola J  Jones RO  Kohara S  Usuki T 《J Phys Condens Matter》2012,24(1):015802

The structure and electronic properties of amorphous Ge(15)Te(85) have been studied by combining density functional (DF) simulations with high-energy x-ray and neutron diffraction measurements. Three models with 560 atoms have been constructed using reverse Monte Carlo methods constrained to (1) agree with the experimental structure factors S(Q), and have (2) energies close to the DF minimum and (3) a semiconducting band structure. The best structure is based on the melt-quenched DF structure and has a small number of Ge-Ge bonds. It shows interlocking networks of Te and GeTe with a significant fraction (22-24%) of voids (cavities). Ge occurs with both tetrahedral and 3 + 3 defective octahedral configurations, and the coordination of Te is slightly higher than indicated by the '8 - N rule' (N is the number of valence electrons). The GeTe network includes clusters of ABAB squares (A = Ge, B = Te), and the bonding is characterized by the chemical bond orders.     

19.

Rotational bands and signature inversion phenomena in πh9/2⊗νi13/2 and πi13/2⊗νi13/2 structures in odd-odd 176Ir     

Y.H. Zhang  M. Oshima  Y. Toh  M. Koizumi  A. Osa  T. Shizuma  T. Hayakawa  M. Sugawara  H. Kusakari  T. Morikawa  S.X. Wen  L.H. Zhu 《The European Physical Journal A - Hadrons and Nuclei》2002,13(4):429-433

The ^109,111,113Rh nuclei have been produced as fission fragments in the fusion reaction ¹⁸O + ²⁰⁸Pb at 85 MeV. Their level schemes have been built from gamma-rays detected using the Euroball IV array. High-spin states of the neutron-rich ^111,113Rh nuclei have been identified for the first time. Several rotational bands with the odd proton occupying the πg _9/2, πp _1/2 and π(g _7/2/d _5/2) sub-shells have been observed. A band of low-energy transitions has been identified at excitation energy around 2 MeV in ^109,111Rh, which can be interpreted in terms of three-quasiparticle excitation, πg _9/2νh _11/2νg _7/2/d _5/2. In addition another structure built on states located at low excitation energy (608 keV in ¹¹¹Rh, 570 keV in ¹¹³Rh) points out that, as already observed in the lighter isotopes ^107,109Rh, triaxial deformation plays a role in the neutron-rich Rh isotopes well beyond the mid-shell. Received: 15 July 2002 / Accepted: 9 October 2002 / Published online: 3 December 2002 RID="a" ID="a"e-mail: porquet@csnsm.in2p3.fr RID="b" ID="b"Present address: CSNSM IN2P3-CNRS and Université Paris-Sud 91405 Orsay, France. RID="c" ID="c"Present address: CEA/Saclay, DSM/DAPNIA/SPhN, 91191 Gif-sur-Yvette Cedex, France. Communicated by D. Schwalm     

20.

The ν6 and 2ν3 bands of CH2DI: Infrared and nuclear quadrupole spectra     

《Journal of Molecular Spectroscopy》1986,119(1):51-55

Pure quadrupole transitions of the iodine nucleus in CH₂DI have been measured by laser-radio frequency double resonance, and analyzed to yield quadrupole coupling constants in the ground, v₆ = 1 and v₃ = 2 states. The corresponding infrared spectra, which were required in order to make assignments, have also been analyzed using Fourier transform data at a resolution of about 0.05 cm⁻¹.     

		$\text{f}{}^1\text{Δ}$		$\text{a}{}^1\text{Δ}$
v	$\text{B}{}_{\mathrm{v}}$	$\text{D}{}_{\mathrm{v}}$ (×106)	$\text{B}{}_{\mathrm{v}}$	$\text{D}{}_{\mathrm{v}}$ (×106)
0	0.502277 (17)	0.6411 (57)	0.536168 (20)	0.5938 (76)
1	0.499198 (32)	0.630 (15)	0.533227 (13)	0.5971 (46)
2			0.530335 (26)	0.636 (13)
	$\text{ω}{}_{\mathrm{e}}\text{= 874.104 (4)}$		$\text{ω}{}_{\mathrm{e}}\text{= 1018.273 (4)}$
	$\text{ω}{}_{\mathrm{e}}\text{χ}{}_{\mathrm{e}}\text{= 2.501 (4)}$		$\text{ω}{}_{\mathrm{e}}\text{χ}{}_{\mathrm{e}}\text{= 4.521 (4)}$
	$\text{T′}{}_{\mathrm{e}}\text{?T″}{}_{\mathrm{e}}\text{= 19140.567 (8)}$

Emission bands of AIH (X1Σ+): The 2-0 sequence

Seven bands of the 2-0 sequence of AlH in its X¹Σ⁺ ground state have been observed in emission from a carbon furnace and recorded with a Bomem interferometer. Improved values for the molecular constants have been obtained. The principal constants are B_e = 6.3937(4), α₃ = 0.1868(3), 10⁴D_e = 3.683(10), ω_e = 1682.43, and ω_eχ_e = 29.11 cm⁻¹, where the error limits are 3σ. Possibilities for observing AlH in astrophysical sources are discussed.     

Temperature dependence of the Mössbauer effect on the semiconductors Pb0.78Sn0.22Te and Pb0.80Sn0.20Te:In

Crystals of the semiconductors Pb_0.78Sn_0.22Te and Pb_0.80Sn_0.20Te:In were grown by Bridgman method, and investigated by Mössbauer spectroscopy and X-ray diffraction. Mössbauer spectra were taken at temperatures between 80 and 300 K. The absence of the quadrupole splitting shows a cubic symmetry of the environment for the tin atom, which is in accordance with X-ray data. The temperature dependence of the spectral area is discussed and the Debye temperature is estimated.     

Ground-state, β and K = 11/2? γ bands in 163, 165Er

Neutron production by stopping 55 MeV deuterons in thick carbon and heavy-water targets has been measured by the activation method. The geometry was close to the one defined for the SPIRAL2 uranium-carbide target in the initial phase. A comparative method for obtaining the neutron flux has been used and is presented in detail. The neutron flux generated by 55 MeV deuterons on carbon is 2.3 times the flux at the deuteron energy of 40 MeV. The flux further increases by a factor 1.4 when using a heavy-water target. These results are discussed in the context of an energy upgrade of the SPIRAL2 driver accelerator.     

The ν1 and ν3 bands of 16O3: Line positions and intensities

Using 0.005 cm⁻¹ resolution Fourier transform spectra of samples of ozone, the ν₁ and ν₃ bands of ¹⁶O₃ have been reanalyzed to obtain accurate line positions and an extended set of upper state rotational levels (J up to 69, K_a up to 20). Combined with the available microwave data, these upper state rotational levels were satisfactorily fitted using a Hamiltonian which takes explicitly into account the strong Coriolis interaction affecting the rotational levels of these two interacting states. In addition, 350 relative line intensities were measured from which the rotational expansions of the transition moment operators for the ν₁ and ν₃ states have been deduced. Finally, a complete listing of line positions, intensities, and lower state energies of the ν₁ and ν₃ bands of ¹⁶O₃ has been generated.     

Can multiband coupling effects due to remote bands cause significant normal-incidence absorption inn-type direct-gap semiconductor quantum wells?

Surprisingly, several experiments have reported that normal-incidence light absorption due to inter-conduction-subband transitions in direct-gap semiconductor quantum wells is as strong as in-plane-incidence absorption. In contrast to other models, a recent theoretical study claimed that a 14-bandk  pmodel including multiband coupling terms due toremote-conduction bandsis able to explain the experimental results. In this work, a concise formulation extends the model beyond 14 bands. Nevertheless, after rederiving the optical transition matrix elements, this analysis clearly shows that the oscillator strength for the in-plane polarized optical intersubband transition due to the multiband coupling effects is much smaller than the oscillator strength for the normal-to-plane polarized optical intersubband transition. These results indicate that the multiband coupling effects due to remote-conduction bands cannot cause a sufficient in-plane polarized optical intersubband transition to produce the observed normal-incidence absorption in the desirablen-type III–V compound semiconductor quantum wells.     

Pre-exponential factor for the crystallization of glassy Se80Te20 and Se75Te20M5 alloys: applicability of Meyer–Neldel rule

The Meyer–Neldel rule or MN rule (also known as compensation effect) is an empirical law known since 1937. This rule is observed in wide range of phenomena in physics, chemistry, biology and electronics. Many activated phenomena, including solid state diffusion in crystals and polymers, dielectric relaxation, conduction and thermally stimulated processes in polymers, and electronic conduction in amorphous semiconductors obey the MN rule. In the present article, we report the MN rule in the non-isothermal crystallization in glassy Se₈₀Te₂₀ and Se₇₅Te₂₀M₅ (M = Ag, Cd, In, Sb) alloys. We have observed MN rule between pre-exponential factor K _o and activation energy of crystallization E _c in the present case for thermally activated non-isothermal crystallization.     

Personal recollections of 52 years of M?ssbauer spectroscopy research

The history of the scientific developments of the M?ssbauer effect, through 52 years, is discussed in terms of personal observations and participation.     

Amorphous Ge??Te??: density functional, high-energy x-ray and neutron diffraction study

The structure and electronic properties of amorphous Ge(15)Te(85) have been studied by combining density functional (DF) simulations with high-energy x-ray and neutron diffraction measurements. Three models with 560 atoms have been constructed using reverse Monte Carlo methods constrained to (1) agree with the experimental structure factors S(Q), and have (2) energies close to the DF minimum and (3) a semiconducting band structure. The best structure is based on the melt-quenched DF structure and has a small number of Ge-Ge bonds. It shows interlocking networks of Te and GeTe with a significant fraction (22-24%) of voids (cavities). Ge occurs with both tetrahedral and 3 + 3 defective octahedral configurations, and the coordination of Te is slightly higher than indicated by the '8 - N rule' (N is the number of valence electrons). The GeTe network includes clusters of ABAB squares (A = Ge, B = Te), and the bonding is characterized by the chemical bond orders.     

Rotational bands and signature inversion phenomena in πh9/2⊗νi13/2 and πi13/2⊗νi13/2 structures in odd-odd 176Ir

The ^109,111,113Rh nuclei have been produced as fission fragments in the fusion reaction ¹⁸O + ²⁰⁸Pb at 85 MeV. Their level schemes have been built from gamma-rays detected using the Euroball IV array. High-spin states of the neutron-rich ^111,113Rh nuclei have been identified for the first time. Several rotational bands with the odd proton occupying the πg _9/2, πp _1/2 and π(g _7/2/d _5/2) sub-shells have been observed. A band of low-energy transitions has been identified at excitation energy around 2 MeV in ^109,111Rh, which can be interpreted in terms of three-quasiparticle excitation, πg _9/2νh _11/2νg _7/2/d _5/2. In addition another structure built on states located at low excitation energy (608 keV in ¹¹¹Rh, 570 keV in ¹¹³Rh) points out that, as already observed in the lighter isotopes ^107,109Rh, triaxial deformation plays a role in the neutron-rich Rh isotopes well beyond the mid-shell. Received: 15 July 2002 / Accepted: 9 October 2002 / Published online: 3 December 2002 RID="a" ID="a"e-mail: porquet@csnsm.in2p3.fr RID="b" ID="b"Present address: CSNSM IN2P3-CNRS and Université Paris-Sud 91405 Orsay, France. RID="c" ID="c"Present address: CEA/Saclay, DSM/DAPNIA/SPhN, 91191 Gif-sur-Yvette Cedex, France. Communicated by D. Schwalm     

The ν6 and 2ν3 bands of CH2DI: Infrared and nuclear quadrupole spectra

Pure quadrupole transitions of the iodine nucleus in CH₂DI have been measured by laser-radio frequency double resonance, and analyzed to yield quadrupole coupling constants in the ground, v₆ = 1 and v₃ = 2 states. The corresponding infrared spectra, which were required in order to make assignments, have also been analyzed using Fourier transform data at a resolution of about 0.05 cm⁻¹.