Fragmented 2d 5/2, 1g 7/2 and 1g 9/2 deep proton-hole states of207TI

The three proton-hole states ?2d_5/2, 1g_7/2 and 1g_9/2 are found to be fragmented as a result of coupling of these states with the 3^?, 5^?, 2⁺, 4⁺ and 6⁺ collective states of²⁰⁸Pb. The excited states in²⁰⁸Pb (t,α) reaction can be quantitatively explained in terms of altered 2d_5/2, 1g_7/2 and 1g_9/2 states with the hole-core coupling model.     

Excited states of154Nd studied through the decay of154Pr

Excited states in the neutron-rich doubly-odd nucleus⁷⁸As have been identified for the first time by proton-γ and γ-γ coincidence measurements via the⁷⁶Ge(α, pn) reaction at 32, 36, and 40 MeV beam energy. Four levels have been found to decay with lifetimes in the nanosecond region. The 5⁽⁺⁾ to (10⁺) states are ascribed to the (πg _9/2?νg _9/2) intruder two-quasiparticle configuration with some collective components in the 9⁽⁺⁾ and (10⁺) states.     

In-beam study of74Br and a first cascade in75Kr

An in-beam study of⁷⁴Br has been carried out using γ-ray spectroscopy in connection with the reactions (³He,p2in) and (d,2n) on⁷⁴Se targets. Separate level schemes on top of the two β-decaying isomers of⁷⁴Br are proposed. Two cascades connecting highspin states are assigned to populate theI ^π=4⁽⁺⁾ isomer. In this level scheme, the excited states at 72.1, 188.3 and 472.0 keV are found to have half-lives of 13.3, 0.7 and 0.7 ns, respectively. The low-spin isomer of⁷⁴Br is tentatively assigned asI ^π=(0^?). This state is populated by two other cascades. For the low-spin levels two-particle configurations of proton and neutron Nilsson orbitals are proposed. The high-spin states are tentatively interpreted as arising from the configurations (πg _9/2,νg _9/2) and (πg _3/2,νg _9/2). As a by-product, a cascade of four transitions has been observed during the³He bombardment of⁷⁴Se and tentatively assigned to negative-parity states in⁷⁵Kr.     

In-beam study of excited states in80Br

Excited states of the doubly-odd nucleus⁸⁰Br have been studied via the reactions⁸⁰Se(p, n),⁸⁰Se(d,2n) and⁷⁸Se(α, pn) using in-beamγ-ray spectroscopy. A positiveparity level sequence built on aI ^π=5⁺ state at 331.04 keV has been found up to spin (10). For this 5⁺ level de-exciting to the known 5^? isomeric state and for the 6⁺ level at 357.22 keV half-lives of 0.7 and 0.4 ns, respectively, have been determined. Negativeparity states have been observed up to spin (6). For the positive-parity level sequence the configuration (πg _9/2,vg _9/2) and collective excitations are proposed. Some of the negative-parity states are tentatively interpreted as arising from the configurations (πp _3/2,vg _9/2) and (πp _3/2, (vg _9/2) ₇ ^2/3 ).     

Low-lying energy levels of the FeH molecule

Multireference configuration interaction (MRCI) and complete active space second-order perturbation theory (CASPT2) calculations are performed on Fe₂ and Fe^? ₂. Although it is not possible to definitively identify the ground states of Fe₂ and Fe^? ₂, the calculations suggest that the ground state of Fe^? ₂ in ⁸Σ^? _u derived from 3d¹³4σ² _g4σ² _u and that the states observed in photodetachment are the ⁹Σ^? _g and ⁷Σ^? _g states with a 3d¹³4σ² _g4σ¹ _u occupation, but that the ground state of Fe₂ is ⁷Δ_u(3d¹⁴4σ² _g) and is not observed in the photo-detachment spectra.     

Structure of high spin states in83Y

We report on the first in-beam study of high spin levels in⁸³Y which were established up to 9.0 MeV excitation energy and probable spin of 41/2⁺ resp. 27/2^? by means of the reaction⁵⁸Ni(²⁸Si, 3p). Ten lifetimes and six lifetime limits in the 10^?12–10^?9 s range were determined in two recoil distance Doppler shift experiments. The positive parity yrast states form ag _9/2 Coriolis decoupled band with partial alignment, near-rigid rotor moment of inertia and deformationβ ₂=0.29. The negative parity yrast band has very similar collective properties; it shows a pronounced band crossing at rotational frequency ?ω≈0.40 MeV which we associate with twoquasiparticleg _9/2 proton alignment. At 2.56 MeV excitation, a second ΔI=1 band starting with 17/2^? was found. On the basis of the similarity to⁸⁵Y and the very weakE2 decay of this state, we suggest that this band has (3qp) configuration with an alignedg _9/2 neutron pair. The lifetimes of the lowest 2⁺ and 4⁺ state in⁸⁴Zr populated in the reaction⁵⁸Ni (²⁸Si, 2p) were determined to be τ(2)=17.8(11) ps resp. τ(4)=3.5(4) ps.     

Accurate theoretical spectroscopic investigations of the 20 Λ-S and 58 Ω states of O2+ cation including the spin–orbit coupling effect

The potential energy curves (PECs) are calculated for the 20 Λ-S states (X²Π_g, A²Π_u, B²Σ^?_g, a⁴Π_u, b⁴Σ^?_g, b′⁴Π_g, c⁴Σ^?_u, 1²Σ⁺_g, 1²Σ⁺_u, 1²Σ^?_u, 1⁴Σ⁺_g, 1⁴Σ⁺_u, 1⁴Δ_g, 1⁴Δ_u, 1⁶Σ⁺_g, 1⁶Σ⁺_u, 1⁶Π_g, 1⁶Π_u, 2⁴Π_g and 2⁴Π_u) of O₂⁺ cation and their corresponding 58 Ω states. Of these 20 Λ-S states, the 1⁶Π_u state is found to be repulsive. The 1²Σ⁺_g, 1⁴Σ⁺_u, c⁴Σ^?_u and 1⁴Δ_u states are found to possess the double well. The b⁴Σ^?_g, 1⁶Σ⁺_g, 1⁴Σ⁺_u, a⁴Π_u, A²Π_u, 1⁶Π_g and 2⁴Π_g states are found to be inverted with the spin–orbit coupling effect included. The b′⁴Π_g, 1⁶Π_g, 1⁶Σ⁺_g, 1⁴Σ⁺_u and 1⁴Δ_u states, and the second well of the 1²Σ⁺_g state are found to be the weakly bound states. The b′⁴Π_g state is found to possess one well with one barrier. The PECs are calculated by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson correction in combination with the aug-cc-pV6Z basis set. The core–valence correlation and scalar relativistic corrections are included. The convergent behaviour of present calculations is discussed with respect to the basis set and theoretical level. The spin–orbit coupling effect is accounted for. The PECs are extrapolated to the complete basis set limit. The spectroscopic parameters are evaluated, and compared with available measurements. It demonstrates that the spectroscopic parameters reported here can be expected to be reliably predicted ones.     

First observation of high spin states in90Tc

High spin states in⁹⁰Tc have been studied via the⁵⁸Ni (³⁵Cl, 2pn) ⁹⁰Tc reaction at beam energy of 124 MeV. Twenty-six newγ-rays were observed, a new level scheme was established and spins were assigned. Two band-like structures were established up to about 20? with an excitation energy of 6–7 MeV. The band (B) shows collective characteristic at high spin. We suggest it to be of a quasi-particle configurationπg_9/2?vf _5/2.     

Yrast states in the doubly-odd nucleus100Tc

High spin states up toJ=14 and excitation energy up toE ^*=3076 keV have been observed in the odd-odd nucleus¹⁰⁰Tc with the reaction⁹⁶Zr(⁷Li, 3n), at bombarding energies between 21 and 31 MeV, by in-beam γ spectroscopy and conversion-electron measurements. A ΔJ=1 negative parity band similar to that observed in theN=57 isotone¹⁰²Rh, and based on the 8^?, 708 keV state has been identified. The observed band can be interpreted in terms of collective core excitations based on a two-quasiparticle state of(πg_9/2 ? νh_11/2) configuration. Comparison with IBFM-2 calculations have been performed.     

First observation of the excited states in the doubly odd nucleus118Cs identified throughγ-recoil coincidences

The previously unknown nucleus¹¹⁸Cs has been identified through γ-γ and γ-recoil coincidences using the GASP γ-spectrometer and Recoil Mass Spectrometer. The level scheme constructed on the base of triple γ coincidences shows a collective structure based on the π^?1g_9/2?νh_11/2 configuration.     

Gamma-ray spectroscopy of87Y

The level structure of⁸⁷Y has been studied using in-beam γ-ray spectroscopic methods. Many previously unknown states have been observed. Members of theπ(g _9/2 )ν(g _9/2)^?2 multiplet are identified. The results are discussed in terms of the weak-coupling model.     

High-K band structures in 164Er

High-spin states of the doubly-odd ¹¹²Sb were studied by in-beam spectroscopy using the ⁸⁸Sr (²⁸Si, p3n) and ⁸⁹Y (²⁹Si, α2n) fusion-evaporation reactions at beam energies of 120 and 108 MeV, respectively. γ?γ, charged particle-γ?γ coincidences, and γ?γ angular correlation analyses were employed for determining the level scheme of ¹¹²Sb. In the present work, all the levels except for low-lying states in ¹¹²Sb were newly established. Two ΔI = 1 strongly coupled bands were observed; one is a negative-parity band that is similar to those observed in the neighboring doubly-odd Sb isotopes and the other is a positive-parity band that has a new type structure not observed in the other isotopes. From the similarity of the properties of these ΔI = 1 bands to the bands built on 9/2⁺ 2p?1h states in the odd-A Sb isotopes, we suggest that these two ΔI = 1 bands should be associated with the [π(g_9/2)^?1 ? νh_11/2] and [π(g_9/2)^?1νg_7/2] configurations, respectively.     

Particle vibration coupling in207Pb

States in²⁰⁷Pb are observed in the proton decay of the lowest 5^? and 4^? analog resonances in²⁰⁸Bi. Evidence is given that one group of these states corresponds to the²⁰⁶Pb(2^ü, 0.8)?g _9/2 and²⁰⁸Pb(3^?, 2.6)?p ₃ ^2/?1 multiplets.     

Anomalies in the orbital magnetism of neutrons in the 190,192Pt nuclei

For the ^190,192Pt nuclei, the g factors of the ν9/2^?[505]?ν11/2⁺[615] 10^? isomeric states populated in the relevant (α, 2n) reactions are measured by the method of an integrated disturbed angular distribution in an external magnetic field. From these measurements, it follows that the g factors are 0.009(8) and 0.010(6) for ¹⁹⁰Pt and ¹⁹²Pt, respectively. From the above g factors, it is found that the anomalous g _l factor of the neutron is δg _l(n)=?0.017(6).     

Electromagnetic transition strengths and nuclear moments in123Xe

The level structure of¹²³Xe has been studied with the¹¹⁴Cd (¹²C, 3n) and^?Cd (¹³C, 4n) reactions using in-beamγ-ray spectroscopy. The yrast cascade on the low lying odd parity states originating from theh _11/2 neutron orbital has been investigated yielding lifetimesτ of 18(3) ps, 2.2 (4) ns and 17(2) ns for the 15/2^?, 11/2^? and 9/2^? states, respectively. Theg-factor of thet _1/2=5.2 μs isomer has been measured to beg=?0.256(2). From the time differential observation of the electric quadrupole interaction in a¹¹⁴Cd single crystal the spin of this isomer has been determined to be 7/2 and from the coupling constante ² Qq/h=116(2) MHz the quadrupole moment was deduced. The results are discussed in the framework of the triaxial rotor plus particle model.     

Reaction mechanism for208Pb(3He,p)210Bi

The double-stripping (³He,p) reaction has been studied on a target of²⁰⁸Pb at 40.8 MeV. Data for the lowest multiplet ofπ h _9/2?v g _9/2 states are compared to a one-step DWBA prediction, a two step sequential single stripping prediction and to a coherent sum of these mechanisms. The two-step mechanism is shown to be much less important than the single step excitation, but its proper inclusion does provide an important improvement to the magnitudes of the predictions. To within a factor of two these calculations account for the magnitudes of the data for final states of spins 0^? through 8^?.     

New isomers and states of (πg 9/2 ⊗vg 9/2) parentage in84Rb

Excited states in the doubly-odd nucleus⁸⁴Rb have mainly been studied via the (α,n) reaction by means of in- beam γ-ray spectroscopy. Two new isomers have been found, a 5^? level at 467.1 keV and a 5⁽⁺⁾ level at 544.2 keV with half-lives of 9(2) ns. and 11(1) ns, respectively. On top of the 5⁽⁺⁾ isomer a level sequence with increasing spins up to 10 ? and probably positive parity has been identified. These states are ascribed to the configuration (πg_9/2?vg_9/2).     

Decay of three-particle high spin states in85Y

High spin states in⁸⁵Y have been excited in the reaction⁷²Ge(¹⁶O,p2n) at 48–60 MeV beam energy. From measurements ofnγ andγγ coincidences, excitation functions and angular distributions, the high spin spectrum of⁸⁵Y has been established up to 5.4 MeV excitation energy and spinI≦29/2. Lifetimes or limits of lifetimes have been determined for 14 levels via the recoil distance and Doppler shift attenuation method. Theg _9/2 decoupled proton band is found to backbend atI ^π=17/2⁺ as also seen in the reduction of the 17/2⁺→13/2⁺ and 21/2⁺→17/2⁺ E2 transition strengths. The lowest (3qp) positive parity band has predominantly aν ² g _9/2×πg _9/2 structure. The observed negative parity yrast states in the spin range 15/2^?≦I≦29/2^? are most probably of (g _9/2)² ×(f _5/2,p _1/2) (3qp) nature as suggested by a comparison of the⁸⁴Sr and⁸⁵Y level structures and electromagnetic transition strengths.     

FastM1 transitions in85Rb

Excited states in⁸⁵Rb have been studied via the⁸²Se(⁷Li, 4n) reaction by using in-beamγ-ray spectroscopy. On the basis of new experimental data on coincidence relations, angular distributions and linear polarizations of theγ-rays the yrast sequence has been extended up to a 33/2⁺ level at 7.1 MeV excitation energy. Using the DSA method mean lifetimes have been determined for 9 levels. Above the 21/2⁺ yrast state 5 fast M1 transitions withB (M 1) ≧0.3 W.u. have been identified. They are interpreted as transitions between recoupled states of the configuration πg_9/2ν(g_9/2) ₈₊ ^?2 or πg_9/2(f ₅ ² /?1p ₃ ^2?1 )₄₊ν(g_9/2) ₈₊ ^?2 .