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1.
肖颖  戴长建  秦文杰 《中国物理 B》2009,18(10):4251-4258
Isolated-core-excitation (ICE) scheme and autoionization detection are employed to study the bound Rydberg states of europium atom. The high-lying states with odd parity have been measured using the autoionization detection method with three different excitation paths via 4f76s6p[ 8P5/2], 4f76s6p[ 8P7/2] and 4f76s6p[ 8P9/2] intermediate states, respectively. In this paper the spectra of bound Rydberg states of Eu atom are reported, which cover the energy regions from 36000~cm-1 to 38250~cm-1 and from 38900~cm-1 to 39500 cm-1. The study provides the information about level energy, the possible J values and relative line intensity as well as the effective principal quantum number n^* for these states. This work not only confirms the previous results of many states, but also discovers 11 new Rydberg states of Eu atom.  相似文献   

2.
This work computed the potential energy curves of 19 Λ-S states, which arose from the first five dissociation limits of BC+ cation, B+(1Sg) + C(3Pg), B+(1Sg) + C(1Dg), B+(1Sg) + C(1Sg), C+(2Pu) + B(2Pu), and B+(1Sg) + C(5Su). The calculations were done for internuclear separations from 0.08 to 1.07 nm. The potential energy curves of 36 Ω states yielded from these Λ-S states were also calculated. Core-valence correlation and scalar relativistic correction, basis set extrapolation as well as Davidson correction were accounted for. Of these Λ-S states, the c1Σ+, D3Π, 21Π, 23Σ+, 21Δ, 31Σ+, and 41Σ+ had double wells; the 33Π and 31Π states had three wells; the C3Σ? and D3Π states were inverted with the spin-orbit coupling effect included; and the second wells of c1Σ+, D3Π and 31Σ+ states, the second and the third wells of 33Π state as well as the third well of 31Π state were very weakly bound, which well depths were smaller than 400 cm?1. The spectroscopic parameters were determined for all the states. The vibrational properties were predicted only for some weakly bound states. The spin-orbit coupling effect on the spectroscopic parameters was evaluated.  相似文献   

3.
Measurements of the decay rates of cascade components of emission from the 31D and 41D states of atomic helium are used to determine the previously unmeasured lifetimes of the 41F and 51F states of Hel. The measured values are 67 ± 10 and 140 ± 14 ns for the 41F and 51F states, respectively.  相似文献   

4.
Spectroscopic constants for the eight lowest electronic states of the NO+ ion are tabulated. These constants result from reanalysis of previously reported optical and photoelectron spectra and interpolation from corresponding states of the isoelectronic molecules CO and N2. Similar spin-orbit perturbations of the A1Π states of NO+ and CO are compared. An interpretation is given of previously reported emission from a beam of long-lived states of NO+. The intensities of ionizing transitions from NO X2Π (v = 0) observed in photoelectron spectra are compared with calculated Franck-Condon factors.  相似文献   

5.
The weak fragments of the 3p1/2, 3p3/2, 2f5/2, 2f7/2 and 1i13/2 proton states of209Bi as seen in the208Pb (3He,d) reaction can be explained with the coupling of the renormalised proton states and the vibrational states of208Pb. The energies of the zerothorder proton shell-model states as well as the collective admixtures of the weak fragmented proton states of209Bi have been deduced from the core-particle coupling model.  相似文献   

6.
《Molecular physics》2012,110(19-20):2445-2454
Different ab initio methods, namely multi-reference and nonorthogonal configuration interaction techniques, are explored for their applicability in studying the singlet fission problem. It has been shown for 2-methyl-1,5-hexadiene that the 1TT state can be identified using multi-reference techniques. The geometrical and vibrational properties of the 1TT state are such that they can be approximated with those of the 5TT state. A proof of principle is given for the calculation of the singlet fission pathway driven by nuclear motion: efficient singlet fission can take place if the 1TT and S1 states are close in energy with a large non-adiabatic coupling matrix element at the S1 geometry, and the energy of the S0 state is well below that of the 1TT state at the 1TT geometry.

The nonorthogonal configuration interaction method was used to treat a tetracene trimer. It has been shown that the first excited states can be interpreted as delocalised states; interaction with charge-transfer base states plays an important role. The 1TT states are localised on one pair of molecules. The electronic coupling between the diabatic S[n] and 1TT[m] states is in the meV range, confirming previous estimates. The charge-transfer base states enhance the coupling between the S[1]/S[2] and 1TT[2] excited states.  相似文献   

7.
Radiative pion capture in 12C and 16O is investigated. An effective interaction Hamiltonian based upon the CGLN theory is employed. Capture rates in 12C and 16O from Is and 2p pionic orbits are calculated by using the nuclear model of Kamimura, Ikeda and Arima for the odd parity states of 12C, and that of Walker with strong ground state correlations, for the odd parity states of 16O. The results are compared with those of the 1p-1h nuclear model under the Tamm-Dancoff and random phase approximations of Gillet and Vinh Mau. Detailed examinations are made for the transitions to low-lying states with 1+ and 2+ for 12C and with 1?, 2? and 3? for 16O by using the Cohen-Kurath and the Walker models, respectively. The results are in good agreement with the recent experimental data from Berkeley.  相似文献   

8.
The two-rotor model0 with the Feshbach projection operator method is applied for investigating the properties of the positive parity low-lying collective states in the rare earth nuclei. The calculations of the energy spectra, E2-transition probability and magnetic properties of the states of β- and γ-bands are carried out for the isotopes 164, 166, 168Er. The B(M1) values from 1+ states to the ground band are estimated.  相似文献   

9.
Pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectra of ArKr have been recorded in the wavenumber range 108,000–118,000 cm?1 using a 1 + 1′ two-photon resonant excitation scheme from the ground X 0+ state of ArKr via selected intermediate states located just below the Ar(1S0) + Kr([5p[1/2]0) dissociation limit. The positions of ionic vibrational levels with quantum numbers from 1 to 30, from 0 to 8 and from 0 to 6 were determined for the X(1/2), A1(3/2) and A2(1/2) states, respectively. The assignment of absolute vibrational quantum numbers of the ionic states was derived from the isotopic shifts of the spectral lines. Combining these data with literature data on the B(1/2) → X(1/2), C1(3/2) → A1(3/2) and C2(1/2) → A2(1/2) band systems of ArKr+ enabled the derivation of potential energy functions for the lowest six electronic states of ArKr+ using a global potential model that includes the effects of the spin-orbit, charge-exchange and long-range interactions.  相似文献   

10.
Ramen Majumdar 《Pramana》1987,29(6):577-581
The high resolution (3He,α) reaction on206Pb shows the distribution of the 2f 7/2, 1h 9/2 and 1i 1 3/2 neutron states of205Pb within the 6 MeV excitation energy of205Pb. The spectrum of these three-hole states is obtained within the hole-core vibrational coupling scheme. The shell model energies of the neutron hole states arising from the core-polarization effect are compared with the Bansal-French energy weighted sum rule. The possible implication of the present neutron hole energies has been discussed in the light of the deduced shell model wave functions of the collective states of206Pb.  相似文献   

11.
《Annals of Physics》1986,171(2):253-296
The F-spin symmetric limits U(5), SU(3), and O(6) of the neutron-proton interacting boson model are studied. The conditions for and consequences of F-spin symmetry are investigated. In each of the three limits closed expressions for the following properties are given: the excitation energies; the M1, E2, and M3 excitation strengths from the ground state to all 1+, 2+, and 3+ states; the M1 and E2 decay of the nonsymmetric 1+ and 2+ states; and the dipole and quadrupole moments of maximal F-spin states and of the nonsymmetric 1+ and 2+ states. The predictions for these properties are compared with the experimental data.  相似文献   

12.
The potential energy curves (PECs) were calculated for the 27 Λ-S states and 73 Ω states of PO radical. The calculations were done using the CASSCF method, which was followed by the internally contracted multireference configuration interaction (icMRCI) approach. To improve the quality of PECs, core-valence correlation and scalar relativistic corrections as well as Davidson correction were included. Of the 27 Λ-S states, the 16Σ+ state was repulsive at any case. The 14Φ and 16Π states were bound, but they became repulsive with the spin-orbit coupling (SOC) effect accounted for. The 34Σ+, a4Π, C′2Δ, D′2Π, 14Δ, 12Φ, 16Σ+ and 16Π states were inverted with the SOC effect included. The F2Σ+ state had double wells. The avoided crossings existed between the B2Σ+ and F2Σ+ states, the F2Σ+ and 32Σ+ states, the C′2Δ and 22Δ states, the 14Δ and 24Δ states, the 24Δ and 34Δ states, the 24Π and 34Π states and the 34Π and 44Π states. The c4Σ+, 24Σ+, 34Σ+, 34Π, 44Π, 54Π, 34Δ, 14Φ and 16Π states were weakly bound, which well depths were within several hundred cm?1. The spectroscopic parameters were derived. The SOC effect on the spectroscopic properties was evaluated. The spectroscopic results obtained here could be expected to be reliably predicted ones.  相似文献   

13.
The three proton-hole states ?2d5/2, 1g7/2 and 1g9/2 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 2d5/2, 1g7/2 and 1g9/2 states with the hole-core coupling model.  相似文献   

14.
124Te核1+态和高自旋态能谱特征的微观研究   总被引:1,自引:0,他引:1       下载免费PDF全文
利用微观sdIBM-2+2q.p.方案,成功地计算出124Te核的低自旋态和部分高自旋态,特别是较成功地再现了1+1,1+2,3+1,3+2和5+1态.基于该方案推出的能量关系指认:6+1,8+关键词: 能谱特征 拆对与顺排 微观sdIBM-2+2q.p.方案 124Te核')" href="#">124Te核  相似文献   

15.
M1 and E1 transition rates from the ground to excited states and between excited states in 238U are calculated within the quasiparticle-phonon nuclear model with the wave functions consisting of one- and two-phonon terms. We show that there are relatively large M1 transitions between 2+ states in the low-energy region. The fragmentation of the one-phonon states strongly affects M1 and E1 strength distributions. The correlation takes place between E1 and E3 transition strengths. We show that there are fast E1 and M1 transitions between large components of the wave functions differing by an octupole or quadrupole phonon.  相似文献   

16.
The neutron strength distributions of the three high-spin 1k 17/2, 2h 11/2 and 1j13/2 states of209Pb have been obtained within the formalism of the core-polarisation effect where the effect of interaction of the neutron shell-model states of209Pb with the collective vibrational states (originating also from the giant resonances) have been taken into consideration. The theoretical results have been discussed in the light of works on 1k 17/2, 2h111/2 and 1j13/2 neutron orbitals of209Pb. The shell-model energies of the neutron states have been obtained by Skyrme-Hartree-Fock method  相似文献   

17.
We have calculated the 01+ ground state and the 02+ and 03+ first excited states of 12C in the model of three α-particles whose interaction is described using a local attractive potential with forbidden states, which well reproduces the α-α scattering phases. The methods of projection of the states forbidden by the Pauli exclusion principle in a system of three composite particles are discussed. The results of the calculation show that the condition of orthogonality to the forbidden states is sufficient to prevent the system from collapse. The binding energy value obtained (15.06 MeV) is somewhat overestimated. This discrepancy seems to come from neglecting triple exchanges of nucleons of different α-particles and from the fact that the 12C real nucleus differs from the 3α system.  相似文献   

18.
The γ-decay and half life of the t1/2=60(3) ns Iπ=8+ isomer in100Cd have been studied with a recoil catcher setup inside the multidetector π-array OSIRIS. Evaporation neutrons and charged particles from the reaction58Ni+46Ti were measured in coincidence with delayed γ-rays. Six new γ-ray transitions with intensities of 1–10% of the main γ-ray cascade were found, two new states established and firm spin-parity assignments were made to all states below the isomer. The new states were identified as the 4+ and 6+ members of the proton πg9/2 ?2 multiplet.  相似文献   

19.
利用自电离探测技术研究Sm原子Rydberg态光谱   总被引:1,自引:0,他引:1       下载免费PDF全文
采用孤立实激发与自电离探测技术相结合的方法对Sm原子偶宇称高激发态进行了系统研究.按照不同的自电离通道将所测数据进行了分类和比较,并进行了详细讨论.不仅报道了许多收敛于不同电离限的Rydberg态的能级位置和跃迁的相对强度等信息,而且还把处于同一能域内的Rydberg态和价态进行了辨识.另外,不但提供了一种有效识别不同类型的高激发态的鉴别技术,而且还对处于41800 cm-1到43800 cm-1能域内的Rydberg态和价态的光谱特性进行了详细分析和讨论. 关键词: 自电离探测 Rydberg态 Sm原子  相似文献   

20.
The M1 transitions between low-lying collective states are discussed from the viewpoint of the Proton-Neutron Interacting Boson Model, with particular emphasis on the mixed-symmetry states. Mixed-symmetry 2+ states are studied for56Fe and54Cr in terms of realistic and large-scale shell-model calculations, including M1 properties. The Doorway-state character of the mixed-symmetry 2+ state is proposed with examples in these nuclei. The possible candidate of the mixed-symmetry 2+ state in134Ba is analyzed based on recent experiment by Molnaret al. on M1 transitions. The M1 transitions from the quasi-γ to quasi-g bands in γ-unstable or O(6) nuclei are discussed next, by taking Ba isotopes as an example. It is suggested that such M1 transitions are enhanced compared to axially symmetric nuclei as an indication of softness towards proton-neutron incoherent motion in γ-unstable nuclei,i.e., mixture of mixed-symmetry states. A new mirror-type symmetry is introduced for γ-unstable nuclei, and the M1 selection rule due to this symmetry is presented, making 4 2 + →4 1 + transition allowed but 3 1 + →2 1 + forbidden, for instance.  相似文献   

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