E0 transition and coupling between quadrupole and pairing-vibrational modes

Using a theory of mode-mode coupling between the two-phonon 0⁺ mode and the pairing-vibrational mode, we have extensively investigated the first excited 0⁺(0₂²) states in spherical and transitional nuclei. The results tell us that the 0₂⁺ states in a wide range of nuclei are strongly mixed states of both the modes. By making use of these results, the matrix elements for the E0 transitions from the 0₂⁺ states to the ground states are calculated for the Zn, Ge, Se, Kr, Sr, Zr, Mo, Ru, Pd, Cd and Sn isotopes. For some of the Cd and Sn isotopes, the matrix elements between the 0₂⁺ and 0₂⁺ states are also obtained. These numerical calculations make a rather good fit to the E0 experiments.     

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.     

Electronic structure and lattice dynamics of CaPd3B studied by first-principles methods

Using first-principles methods, we have studied the electronic structure and lattice dynamics of CaPd₃B and compared them to isostructural MgNi₃C. CaPd₃B possesses less electronic states at the Fermi level, but more phonon modes at low frequencies, than MgNi₃C. According to the phonon density of states, low frequency acoustic modes are dominated by Pd states, corresponding to Ni in MgNi₃C. Furthermore, these Pd modes show soft phonons, which may be significant for second-order phase transitions. Based on the comparison to MgNi₃C, we suggest that the properties of these two compounds may be similar.     

Charge-transfer states and optical absorption

The intensities of the Laporte-forbidden transitions in complexes like RhCl₆ ^3-, IrBr₆ ^2-, etc. are connected to the energies of the initial, final and charge-transfer states by the approximate relation, intensity α(E_f - E_i ) (E_C - E_f )^-2. This is due to the mixing in of the odd, bonding states into the even, anti-bonding ones through the vibrations of the complex. An analysis of the electronic states of these strongly covalent complexes and of the allowed, charge-transfer transitions is also presented. From this it is concluded that the dipole moment of the transitions is largely due to the presence of the charges in the anti-bonding states on the ligand due to covalent bonding.     

Al65Cu20Fe15 in amorphous,crystalline and quasicrystalline states

Three structurally distinct states (amorphous, crystalline, and quasicrystalline) of Al₆₅Cu₂₀Fe₁₅ and neighboring compositions, have been observed. A new metastable state. Intermediate between the amorphous and the quasicrystalline states, has been found. Mössbauer-effect measurements on these samples Al₆₅Cu_20xFe_15+x (?10≤x≤ 10, at.%) In the three different states show that the differences in the effective isomer shifts and quadrupole splittings among the three states are small despile diametrically different structures.     

Theoretical study of molecular properties of low-lying electronic excited states of H2O and H2S

Geometries, excitation energies, dipole moments and dipole polarisability tensor components of the ground and four lowest excited states ³ B ₁, ¹ B ₁, ³ A ₂, ¹ A ₂ of the H₂O and H₂S molecules were calculated at the CASSCF, CASPT2, CCSD and CCSD(T) level of approximation. Vertical excitation and equilibrium transition energies of these states, having the Rydberg character, are reported too. Properties of both molecules in the ground and in low lying excited states are compared and discussed from the point of view of their molecular electronic structure. Upon excitation we observe dramatic changes of dipole moments and polarisabilities with respect to the ground state. We stress the change of the polarity of H₂O in all excited states accompanied by the enhancement of the dipole polarisability by an order of magnitude. Large, even if less pronounced, are changes of electric properties of H₂S in its excited states. Dipole moments and dipole polarisabilities of ³ B ₁, ¹ B ₁ states of H₂S and H₂O behave quite analogously in comparison to their respective ground state. The general pattern of properties for both molecules in their ³ A ₂ and ¹ A ₂ excited states is more different due to a pronounced participation of the sulphur d-orbitals in these states of the H₂S molecule.     

Crystallized schrödinger cat states

Crystallized Schrödinger cat states (male and female) are introduced on the base of extension of group construction for the even and odd coherent states of the electromagnetic field oscillator. The Wigner and Q functions are calculated and some are plotted forC ₂,C ₃,C ₄,C ₅,C _3v Schrödinger cat states. Quadrature means and dispersions for these states are calculated and squeezing and correlation phenomena are studied. Photon distribution functions for these states are given explicitly and are plotted for several examples. A strong oscillatory behavior of the photon distribution function for some field amplitudes is found in the new type of states.     

Electronic structure of MgS and MgYb2S4: Electron Energy-Loss Spectroscopy and self-consistent multiple scattering calculations

The electronic structure of MgS and MgYb₂S₄ have been studied using the fine structure of the Mg-K, S-K, Mg-L_2,3, S-L_2,3 and Yb-N₅ edges measured by electron energy-loss spectroscopy (EELS). Our experimental results are compared with real-space full multiple scattering calculations as incorporated in the FEFF9.6 code. All edges are very well reproduced. Total and partial densities of states have been calculated. The calculated densities of states of Mg and S are similar in both compounds. The energy distribution of these states suggests a covalent nature for both materials. For MgYb₂S₄ a band gap smaller than for MgS is predicted. In this compound the top of the valence band and the bottom of the conduction band are dominated by Yb states.     

Confrontation between the quasiparticle-phonon nuclear model and the interacting boson model for deformed nuclei

TheK ^π=0⁺, 2⁺ and 4⁺ states are considered in doubly even deformed nuclei. It is shown that in the quasiparticle-phonon nuclear model (QPNM) and in the interacting boson model (IBM) a vibrational state has one dominating component. The states withK _n ^π =0 ₃ ⁺ , 0 ₄ ⁺ 0 ₅ ⁺ 2 ₂ ⁺ , 2 ₃ ⁺ , 4 ₁ ⁺ and 4 ₂ ⁺ have a dominating one-phonon component within the QPNM and a two- or three-boson component within the IBM. According to the QPNM the contribution of two-phonon components to the wave functions of these states is less than 10%, i.e. there is a qualitative discrepancy in describing the structure of these states within the QPNM and the IBM. The experimental data indicate the existence in these states of one-phonon or two-quasiparticle components. They are rather well described within the QPNM. These states cannot be described within the IBM. This is due to the fact that the IBM takes into account only a small part of the space of two-quasiparticle states, just the one entering intoΒ- andγ-vibrational states.     

Local and quasi-local vibrational modes of Si in Ge

We report far infrared absorption spectra of crystalline Ge_0.89 Si_0.11 and Ge_0.84Si_0.16 at 300 and 77 K in the range 40–430 cm^-1. We have observed in these data several mass defect quasi-bound vibrational states and impurity induced one-phonon peaks. The results are interpreted with a mass defect Green's function calculation based on the density of phonon states of pure c-Ge.     

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.     

S掺杂对锐钛矿相TiO2电子结构与光催化性能的影响

采用基于第一性原理的平面波超软赝势方法研究了掺杂不同价态S的锐钛矿相TiO₂的晶体结构、杂质形成能、电子结构及光学性质.计算结果表明硫在掺杂体系中的存在形态与实验中的制备条件有关;掺杂后晶格发生畸变、原子间的键长及原子的电荷量也发生了变化,导致晶体中的八面体偶极矩增大; S 3p态与O 2p态、Ti 3d态杂化而使导带位置下移、价带位置上移及价带宽化,从而导致TiO₂的禁带宽度变窄、光吸收曲线红移到可见光区.这些结果很好地解释了S掺杂锐钛矿相TiO₂在可见光下具有优良的光催化性能的内在原因.根据计算结果分析比较了硫以不同离子价态掺杂对锐钛矿相TiO₂电子结构和光催化性能影响的差别. 关键词： 2')" href="#">锐钛矿相TiO₂ S掺杂 第一性原理 光催化性能     

Wavefunction symmetries and binding energies in GaSxSe1−x compounds

We report on a synchrotron radiation photoemission spectroscopy study of mixed GaS_xSe_1?x crystals. The most prominent composition effect in the valence band is an increase by ～ 0.4 eV of the energy separation between the p_z states and the p_x, p_y states as x increases from 0 to 1. The repulsion in energy is accompanied by a progressive mixing of these states in k-space regions far from the zone boundaries.     

An ultrafast time‐resolved infrared and UV–vis spectroscopic and computational study of the photochemistry of acyl azides

The photochemistry of pivaloyl, benzoyl, 4‐phenylbenzoyl, and 2‐anthroyl azides has been studied using femtosecond (fs) time‐resolved infrared (TRIR) and UV–vis spectroscopy and interpreted with the aid of computational chemistry. Density functional theory calculations revealed a significant difference in the nature of the lowest singlet excited state for these carbonyl azides. The lowest singlet excited states (S₁) of p‐phenylbenzoyl and 2‐anthroyl azides are (π,π*) in nature, while the pivaloyl and benzoyl azides S₁ states involve (n,π*) excitations. Nevertheless, for all acyl azides studied here, a similar, and intense, IR band at about 2100 cm^?1 has been detected in the ultrafast TRIR experiments following 270 nm excitation. These bands were shifted to lower energy by about 100 cm^?1 relative to the N₃ stretching mode for the ground states of these azides. These 2100 cm^?1 vibrational bands were assigned to the S₁ states of acyl azides in agreement with density functional theory calculations. The decay of the acyl azide S₁ states was described by bi‐exponential functions. The fast component was attributed to the decay of the hot S₁ state and the longer component to the decay of the thermally relaxed S₁ state. A strong and broad transient absorption in the 350–650 nm spectral range was observed in the fs UV–vis experiments for p‐phenylbenzoyl and 2‐anthroyl azides. The carrier of this absorption also decayed bi‐exponentially, and the time constants were in excellent agreement with those found in the fs TRIR experiments. The slow component of the S₁ state decay was found to be dependent on the solvent polarity. When the lifetime of the acyl azide S₁ state is substantially longer than the time constant for vibrational cooling of nascent (hot) isocyanate, the correlation between the S₁ decay and isocyanate formation was clear. The 270 nm excitation populates the S_n (n ≥ 2) states of these acyl azides. It was established that a hot nitrene is produced more efficiently from both the S_n and hot S₁ states than from the relaxed S₁ state of these acyl azides. Thus, time‐resolved study provides direct experimental evidence that the S₁ state is the precursor of nitrene only when the S₁ state is pumped directly and when the S₁ state lifetime is longer than the time constant of vibrational cooling of the newborn nitrene. All of these results are consistent with the data obtained recently for 2‐napththoyl azide. Copyright © 2012 John Wiley & Sons, Ltd.     

Dissociation Energies of XO+ g and AO+ u States of Gaseous Te2

Experimental potential energy curves have been constructed for XO⁺ _g and AO⁺ _u states of gaseous Te₂ by partial numerical integration directly. Then the dissociation energies for these states have been estimated by fitting the H[sbnd]H function to the experimental potential energy curves.     

First-principles study on alloying stability, electronic structure, and mechanical properties of Al-based intermetallics

First-principles calculations were performed to study on alloying stability, electronic structure, and mechanical properties of Al-based intermetallic compounds (AlCu₃, AlCu₂Zr, and AlZr₃). The calculated results show that the lattice parameters obtained after full relaxation of crystalline cells are consistent with experimental data. The calculation of cohesive energies indicated that the structure stability of these Al-based intermetallics will become higher with increasing Zr element in crystal. The calculations of formation energies showed that AlCu₂Zr has the strongest alloying ability, followed by AlZr₃ and finally the AlCu₃. The further analysis find out that single-crystal elastic constants at zero-pressure satisfy the requirement of mechanical stability for cubic crystals. The calculations on the ratio of bulk modulus to shear modulus reveal that AlCu₂Zr can exhibit a good ductility, followed by AlCu₃, whereas AlZr₃ can have a poor ductility; however, for stiffness, these intermetallics show a converse order. The calculations on Poisson's ratio show that AlCu₃ is much more anisotropic than the other two intermetallics. In addition, calculations on densities of states indicate that the valence bonds of these intermetallics are attributed to the valence electrons of Cu 3d states for AlCu₃, Cu 3d, and Zr 4d states for AlCu₂Zr, and Al 3s, Zr 5s and 4d states for AlZr₃, respectively; in particular, the electronic structure of the AlZr₃ shows the strongest hybridization, leading to the worst ductility.     

The millimeter-wave spectra of germyl fluoride in excited vibrational states

Millimeter-wave spectra of GeH₃F in the v₃ = 1, v₆ = 1, v₂ = 1, and v₅ = 1 excited states have been recorded. Strong Coriolis resonance between the v₂ = 1 and v₅ = 1 states results in a highly perturbed spectrum which shows no obvious resemblance to the normal symmetric top excited state pattern. A similar, but not so strong coupling, exists between the v₃ = 1 and v₆ = 1 states. These spectra are analyzed by setting up the Coriolis coupled Hamiltonian matrices for these states. It has been shown that the apparently anomalous distortion constants of these states are due to the Coriolis coupling and the distortion parameters obtained with the model presented are, as expected, close to the ground state values.     

Rydberg states of carbon dioxide and carbon disulfide

The electronic absorption spectra of carbon dioxide and carbon disulfide have been reexamined. Model potential calculations have been used to calculate the energies of excited states in Rydberg approximation, and (npσ) and (npπ) Rydberg series have been assigned. For both molecules, the lowest excited ¹Π_g and ¹Π_u states are identified as Rydberg states. The lowest ${}^1\text{Σ}{}_{\mathrm{u}}{}^{\mathrm{+}}$ state is mainly Rydberg for CO₂, but contains some valence character for CS₂, There is no evidence for transitions to additional valence states of these symmetries.It is shown that $\text{LCAO}\text{MO}$ predictions about excited states can be misleading because of near-linear dependencies which arise in multicenter expansions. A consideration of the united atom orbitals for CO₂ and CS₂ predicts that there should be only the number of low-energy excited states which are found from the spectral analysis.     

高双激发Intershell共振态的辐射和Auger跃迁率

采用Conventional infiguration(简写为CI)方法计算了类氦Ar¹⁶⁺离子高双激发Intershell(n>N)共振态的辐射和Auger跃迁率,并利用超球坐标方法和新量子数_n(K,T)_N^A2s+1L^π来作系统分析。计算结果表明,对A=+1态,Auger过程是主要的,辐射过程仅仅是对给定的多重簇(manifold)中更高的态才有意义。对A=0,-1态,Auger宽度更小。对这些 关键词：     

Excitation of inner-shell states of CO2, COS,CS2, N2O and C2H2 by low energy electron impact

The design of an electron impact spectrometer for use in the study of inner-shell electric-dipole-forbidden transitions is described. The use of the spectrometer to investigate spin-forbidden transitions to inner-shell excited states of CO₂, COS, CS₂, N₂O and C₂H₂ is reported. For all these molecules, excitation of inner-shell triplet states has been observed.