Bound states and resonance states of the plasma-embedded tdμ and ddμ molecular ions

We have investigated the bound states and resonance states of plasma-embedded tdμ and ddμ molecular ions using accurate correlated basis functions. The plasma effect has been taken care of by considering the Debye shielding approach of plasma modeling which admits a variety of plasma conditions. The density of resonance states are calculated using the stabilization method. The ground and excited states energies, and the S-wave resonance energies of tdμ and ddμ molecular ions immersed in plasmas are reported for various shielding parameters, along with the 1S and 2S threshold energies of the tμ and dμ atoms.     

Accurate spectroscopic calculations of the 19 Λ-S states and 36 Ω states of the BC+ cation

This work computed the potential energy curves of 19 Λ-S states, which arose from the first five dissociation limits of BC⁺ cation, B⁺(¹S_g) + C(³P_g), B⁺(¹S_g) + C(¹D_g), B⁺(¹S_g) + C(¹S_g), C⁺(²P_u) + B(²P_u), and B⁺(¹S_g) + C(⁵S_u). 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.     

Structure and stability of various states of the EuC and EuC2 molecules

B3LYP level density functional theory （DFT） and multiconfiguration self-consistent-field （MCSCF） level ab initio method calculations have been performed on the basis of relativistic effective core potentials to investigate the nature of EuC and EuC2 molecules. The computed results indicate that the ground states of EuC and EuC2 are ^12∑^＋ and SA2, respectively. Dissociation potential energy curves of the low-lying electronic states of EuC have been calculated using the MCSCF method, and the same level calculation on EuC2 indicates that the dissociation energy of EuC2 of ground state compares well with the available experimental data. The bond characteristic is also discussed using Mulliken populations.     

Phase and population decay of image-potential states – the influence of defects

Quantum-phase and population decay of image-potential states have been investigated by two-photon photoemission with femtosecond time resolution. The influence of steps and defects on quasielastic and inelastic scattering processes is illustrated for a vicinal Cu(119) surface and diluted adsorbate layers of CO and Cu on Cu(001). Received: 19 April 2000 / Accepted: 2 September 2000 / Published online: 12 October 2000     

Reanalysis of the mass spectrum of the scalar hidden charm and hidden bottom tetraquark states

In this article, we study the mass spectrum of the scalar hidden charm and hidden bottom tetraquark states which consist of the axial-vector–axial-vector type and the vector–vector type diquark pairs with the QCD sum rules.     

Ab initio configuration interaction study of the ground and low-lying excited states of ZnCd

The multi-reference configuration interaction (MRCI) electronic energy calculations have been carried out on the ground state (X~1∑) as well as three low-lying excited states (~3E,~1∏,~3∏) of ZnCd dimer.Poten- tial energy curves (PECs) are therefore generated and fitted to the analytical potential energy functions (APEFs) using the Murrel-Sorbie (MS) potential function.Based on the PECs,the vibrational levels of each state are determined by solving Schr(?)dinger equation of nuclear motion,and corresponding spec- troscopic parameters are accurately calculated using the APEFs.The present values of spectroscopic parameters including equilibrium positions and dissociation energies are compared with other theoretical reports available at present.     

Ab initio potential surfaces for the à and states of HCN+

Ab initio configuration interaction calculations for the à ²Σ⁺ and states of HCN⁺ are presented. Minima occur at r _CH = 2·03 a ₀, r _CN = 2·25 a ₀ (à ²Σ⁺) and r _CH = 2·75 a₀, r _CN = 2·26 a ₀ (). The potential surface for the state has a local maximum as the hydrogen atom is pulled away from CN. The barrier height is calculated to be 0·27 eV.     

Generalized path-integral solution and coherent states of the harmonic oscillator in D-dimensions

We construct a general form of propagator in arbitrary dimensions and give an exact wavefunction of a time- dependent forced harmonic oscillator in D（D ≥ 1） dimensions. The coherent states, defined as the eigenstates of annihilation operator, of the D-dimensional harmonic oscillator are derived. These coherent states correspond to the minimum uncertainty states and the relation between them is investigated.     

Analysis of the pseudoscalar partner of the Y(4660) and related bound states

In this article, we study the pseudoscalar bound state η _c ′f ₀(980) (irrespective of the hadro-charmonium and the molecular state) with the QCD sum rules. Considering the SU(3) symmetry of the light flavor quarks and the heavy quark symmetry, we also study the bound states η _c ′σ(400?1200), η _b '''f ₀(980) and η _b '''σ(400?1200), and make reasonable predictions for their masses.     

Accurate calculations of the 18 Λ-S states and 50 Ω states of PO+ cation: potential energy curves and spectroscopic parameters including the spin-orbit coupling effect

The potential energy curves (PECs) of 5 Ω states generated from the 18 Λ-S states (X ¹ Σ ⁺, A¹Σ^?, 1¹ Δ, 1¹ Π, 2¹Σ⁺, 2¹ Π, a ³ Σ ⁺, 1³ Δ, 1³ Π, 1³Σ^?, 2³Σ⁺, 2³ Π, 1⁵Σ⁺, 1⁵ Π 2⁵ Π, 1⁵Σ^?, 2⁵Σ⁺ and 1⁵ Δ) of PO⁺ cation are studied for the first time for internuclear separations from about 0.08 to 1.0 nm. Of these Λ-S states, only the 2⁵Σ⁺ and 1⁵ Δ are the replusive ones. The a ³ Σ ⁺, 2³Σ⁺, 1⁵Σ^?, 2³ Π, 1³ Δ, 2⁵Σ⁺ , and 1⁵ Δ are the inverted states with the spin-orbit coupling effect included. The 1¹ Π, 1³ Π, 1⁵ Π and 2³ Π states possess the double well. The 1⁵Σ^?, 2¹ Π and 2⁵ Π states and the second wells of 1¹ Π, 1³ Π, 2³ Π and 1⁵ Π states are the rather weakly bound states. The PEC calculations are performed by the CASSCF method, which is followed by the icMRCI approach with Davidson correction in combination with the aug-cc-pV6Z basis set. Core-valence correlation and scalar relativistic corrections are included at the same time. The spin-orbit coupling effect is accounted for. All the PECs are extrapolated to the complete basis set limit. The spectroscopic parameters are evaluated for all the Λ-S and Ω bound states, and compared with the measurements and other theoretical results. Fair agreement is found between the present spectroscopic parameters and the measurements. The vibrational properties are evaluated for the weakly bound states. The effect of spin-orbit coupling on the spectroscopic parameters is discussed. The results reported in this paper can be expected to be reliable predicted ones.     

Accurate spectroscopic calculations of the 12 Λ-S states and 27 Ω states of NF+ cation including the spin–orbit coupling effect

This paper studies the potential energy curves (PECs) of 27 Ω states generated from the 12 Λ-S states (X²Π, 1²Σ⁺, 1²Σ^?, 2²Σ^?, A²Π, 1²Δ, 1⁴Σ⁺, 1⁴Σ^?, 2⁴Σ^?, 1⁴Π, 2⁴Π and 1⁴Δ), which are attributed to the first dissociation channel of NF⁺ cation. Of these 12 states, only 2²Σ^? and 2⁴Π are the repulsive ones, which are very different from those reported by G.-S. Kim and D. M. Hirst, Mol. Phys. 86, 1183–1193 (1995) G.-S. Kim and D.M. Hirst, Mol. Phys. 86, 1183–1193 (1995).[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]. In addition, the 1²Δ and 1⁴Σ^? states are found to possess the double well. 1⁴Σ⁺, 1⁴Σ^? and 1⁴Δ are found to be the inverted states with the spin–orbit coupling effect taken into account, and 1²Σ⁺, 1²Σ^?, 1²Δ, 1⁴Σ⁺, 2⁴Σ^? and 1⁴Δ are found to be the weakly bound states. 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 Davidson correction. The convergent behaviour of the present calculations is discussed with respect to the basis set and level of theory. All the PECs are extrapolated to the complete basis set limit. Core–valence correlation and scalar relativistic corrections are included at the same time. The spin–orbit coupling effect is accounted for by the state interaction method with the Breit–Pauli Hamiltonian. The spectroscopic parameters are evaluated and compared with available measurements and other theoretical results. The effect of spin–orbit coupling on the spectroscopic parameters is discussed. The Franck–Condon factors and radiative lifetimes of the transitions from the 1⁴Π_3/2, 1⁴Σ^?_3/2, 1²Δ_3/2 and A²Π_1/2 states to the X²Π_1/2 state are calculated for several low vibrational levels and some necessary discussion is done. It shows that the spectroscopic results reported in this paper can be expected to be reliably predicted ones.     

Influence of caged noble-gas atom on the superatomic and valence states of C60−

Using high-level ab initio coupled cluster methods, we have conducted a detailed study of two endofullerene anions, He@C^?₆₀ and Ne@C^?₆₀. The main focus was on elucidating the effect of the noble-gas atom on the energy and electronic structure of the stable anion states of the parent C^?₆₀. Our study revealed that the noble-gas atom has no influence on the valence-like states of C^?₆₀, but strongly affects the superatomic-like ²A_g state. The latter was found to undergo pronounced destabilisation in both the He@C^?₆₀ and Ne@C^?₆₀ species, losing more than 70% of its original electron binding energy. The observed destabilisation is due to perturbation of the excess electron density of the ²A_g state inside the C₆₀ cage by the caged noble-gas atom. We show how the results of our analysis can be used to predict the behaviour of the ²A_g state in other closed-shell endohedral complexes. Some possible implications of the observed features of the ²A_g state are discussed.     

Radial excitation states of η and η′ in the chiral quark model

A chiral quark model is applied to calculate the spectra of pseudoscalar mesons η and η . By analyzing the obtained spectra, we find that the mesons η (2 1 S 0 ), η(4 1 S 0 ), η (3 1 S 0 ) and η (4 1 S 0 ) are the possible candidates of η(1760), X(1835), X(2120) and X(2370). The strong decay widths of these pseudoscalars to all the possible two-body decay channels are calculated within the framework of the 3 P 0 model. Although the total width of η (21S0 ) is compatible with the BES Collaboration’s experimental value for η(1760), the partial decay width to ωω is too small, which is not consistent with the BES result. If X(1835) is interpreted as η(4 1 S 0 ), the total decay width is compatible with the experimental data, and the main decay modes will be πa 0 (980) and πa 0 (1450), which needs to be checked experimentally. The assignment of X(2120) and X(2370) to η (31S0 ) and η (41S0 ) is disfavored in the present calculation because of the incompatibility of the decay widths.     

Radial excitation states of η and η' in the chiral quark model

A chiral quark model is applied to calculate the spectra of pseudoscalar mesons η and η'. By analyzing the obtained spectra, we find that the mesons η'(2¹S₀), η(4¹S₀), η'(3¹S₀) and η'(4¹S₀) are the possible candidates of η(1760), X(1835), X(2120) and X(2370). The strong decay widths of these pseudoscalars to all the possible two-body decay channels are calculated within the framework of the ³P₀ model. Although the total width of η'(2¹S₀) is compatible with the BES Collaboration's experimental value for η(1760), the partial decay width to ωω is too small, which is not consistent with the BES result. If X(1835) is interpreted as η(4¹S₀), the total decay width is compatible with the experimental data, and the main decay modes will be mπ a₀(980) and m π a₀(1450), which needs to be checked experimentally. The assignment of X(2120) and X(2370) to η'(3¹S₀) and η'(4¹S₀) is disfavored in the present calculation because of the incompatibility of the decay widths.     

Mössbauer study of the vibrational anisotropy and of the light-induced population of metastable states in single-crystalline guanidinium nitroprusside

M?ssbauer studies were performed on single crystals of guanidinium nitroprusside with different orientations of their principal crystallographic axes (a, b, c) with respect to the incident radiation. The markedly anisotropic Lamb-M?ssbauer factor f _LM , i.e. f _LM ^(a) = 0.118(8), f _LM ^(b) = 0.174(8), f _LM ^(c) = 0.202(8) is in contrast to that of nitroprussides with inorganic anions. The observed anisotropy is ascribed to the anisotropic vibrational mean-square displacement of the nitroprusside anions as a whole which is due to the specific packing of both, anions and cations, as well as the very weak chemical bonding between the ions, typical only for guanidinium nitroprusside. The vibrational anisotropy of iron atoms in barium nitroprusside that has been observed by X-ray structural investigations has a different origin and therefore does not result in an anisotropic Lamb-M?ssbauer factor. We have also investigated metastable states in guanidinium nitroprusside that have been populated by means of incoherent irradiation from light-emitting diodes. With a specific orientation of the guanidinium nitroprusside single crystal a population of the metastable states up to 26% could be achieved. Populations of comparable size on lithium, sodium and potassium nitroprussides have only been reached using coherent laser irradiation. Received 15 December 1998 and Received in final form 3 March 1999     

Analysis of the 1S and 2S states of AQ and ΘQ with QCD sum rules

In this article,we study the ground states and the first radial excited states of the flavor antitriplet heavy baryon states AQ and ΘQ with the spin-parity JP =...     

Radial excitation states of η and η' in the chiral quark model

A chiral quark model is applied to calculate the spectra of pseudoscalar mesons η and η'. By analyzing the obtained spectra, we find that the mesons η'(2¹S₀), η(4¹S₀), η'(3¹S₀) and η'(4¹S₀) are the possible candidates of η(1760), X(1835), X(2120) and X(2370). The strong decay widths of these pseudoscalars to all the possible two-body decay channels are calculated within the framework of the ³P₀ model. Although the total width of η'(2¹S₀) is compatible with the BES Collaboration's experimental value for η(1760), the partial decay width to ωω is too small, which is not consistent with the BES result. If X(1835) is interpreted as η(4¹S₀), the total decay width is compatible with the experimental data, and the main decay modes will be mπ a₀(980) and m π a₀(1450), which needs to be checked experimentally. The assignment of X(2120) and X(2370) to η'(3¹S₀) and η'(4¹S₀) is disfavored in the present calculation because of the incompatibility of the decay widths.     

Revised molecular constants and term values for the XΣ and AΠ states of NH

The vibration–rotation spectra of NH have been reinvestigated using laboratory spectra and infrared solar spectra recorded from orbit by the ACE and ATMOS instruments. In addition to identifying the previously unobserved 6–5 vibration–rotation band in the laboratory spectra, many additional high N rotational lines have been observed. By combining the new observations with the previously published data and recent far infrared data, an improved set of molecular constants and term values have been derived for the X³Σ⁻ and A³Π states.     

NMR analogue of the generalized Grover‘s algorithm of multiple marked states and its application

The generalized Grover's algorithm for the case in which there are multiple marked states is demonstrated on a nuclear magnetic resonance (NMR) quantum computer. The Walsh－Hadamard transform and the phase inversion are all replaced. NMR analogues of Einstein－Podolsky－Rosen states (pseudo-EPR states) are synthesized using the above algorithm.     

Ab initio study of the spectroscopy of the XΠ electronic ground states of CNO and NCO

The X²Π electronic ground states of NCO and CNO have been investigated by complete ab initio methods. The dependence of the Renner-Teller parameters, ? and , on the ab initio method and on the basis set have been studied. These parameters have also been compared to experimental data for NCO. The potential energy surfaces of the X²Π state have been determined by the MRCI method and the cc-pVQZ basis set for NCO and CNO. The rovibronic levels of both isomers have been calculated variationally up to approximatively 4000 cm⁻¹ for J ? 5/2 and K ? 2, with the inclusion of the geometry dependence of the spin-orbit coupling. The agreement with experimental data obtained for NCO is remarkable. A similar accuracy for the ab initio rovibronic levels of CNO is expected since no experimental data exists for this isomer.