Low-lying valence and Rydberg states of NS, obtained by configuration-interaction studies

Using double-ζ plus polarization basis sets with diffuse s and p functions on N and S, configuration-interaction calculations were carried out for low-lying valence and Rydberg states of NS. In general, there is good agreement with experimentally obtained spectroscopic constants, and with theoretical results obtained by other groups. The avoided crossing of 2²Σ⁺(C) and 3²Σ⁺(I), and the reported predissociation from low vibrational levels of the C state received particular attention.     

The electronic states of silicon monofluoride: Low-lying valence states

Hartree-Fock and configuration interaction calculations are reported for the lowest valence state of the SiF molecule. Deduced spectroscopic constants are in good agreement with the experimental values. The dipole moment calculated for SiF is consistent with a charge distribution corresponding to a Si⁺F^? configuration.     

The electronic states of carbon monofluoride: Low-lying valence states

Multiconfiguration Hartree-Fock calculations are reported on the low-lying valence states, the X²Π, ⁴Σ^?, B²Δ, and ²Σ^± states, of carbon monofluoride. The wavefunctions describe dissociation of the molecule to the correct atomic limits and take account of the atomic 2s-2p near-degeneracy effect. For the ground state the calculations give (with experimental values in parentheses): a bond length of 1.286 Å (1.2667 Å), a fundamental frequency of 1292 cm^?1 (1308 cm¹), and a dissociation energy of 3.93 eV (5.5 ± 0.1 eV). A ⁴Σ^? state arising from the $\text{C}\text{(}{}^3\text{P) +}\text{F}\text{(}{}^2\text{P)}$ manifold is calculated to lie just 2.66 eV above the ground state. The B²Δ state, calculated adiabatic excitation energy 6.59 eV (6.12 eV), is found to dissociate to $\text{C}\text{(}{}^1\text{D) +}\text{F}\text{(}{}^2\text{P)}$ via a potential maximum. Calculations are also reported on a repulsive ²Δ state arising from ground state atoms.     

Low-lying electronic states of aluminum monoiodide

High-level ab initio calculations of aluminum monoiodide(AlI) molecule are performed by utilizing the multireference configuration interaction plus Davidson correction(MRCI+Q) method. The core-valence correlation(CV) and spin–orbit coupling(SOC) effect are considered. The adiabatic potential energy curves(PECs) of a total of 13 Λ–S states and 24 ? states are computed. The spectroscopic constants of bound states are determined, which are in accordance with the results of the available experimental and theoretical studies. The interactions between the Λ–S states are analyzed with the aid of the spin–orbit matrix elements. Finally, the transition properties including transition dipole moment(TDM),Frank–Condon factors(FCF) and radiative lifetime are obtained based on the computed PEC. Our study sheds light on the electronic structure and spectroscopy of low-lying electronic states of the AlI molecule.     

Low-lying electronic states of CuN calculated by MRCI method

The high accuracy ab initio calculation method of multi-reference configuration interaction(MRCI) is used to compute the low-lying eight electronic states of CuN.The potential energy curves(PECs) of the X~3∑~-,1~3Π,2~3∑~-,1~3△,1~1△,1~1∑~-,1~1Π,and ~5∑~- in a range of R=0.1 nm-0.5 nm are obtained and they are goodly asymptotes to the Cu(~2S_g) + N(~4S_u) and Cu(~2S_g)+N(~2D_u) dissociation limits.All the possible vibrational levels,rotational constants,and spectral constants for the six bound states of X~3∑~-,1~3Π,2~3∑~-,1~1△,1~1∑~-,and 1~1 Π are obtained by solving the radial Schrdinger equation of nuclear motion with the Le Roy provided Level 8.0 program.Also the transition dipole moments from the ground state X~3∑~- to the excited states 1~3Π and 2~3∑~- are calculated and the result indicates that the 2~3∑-X~3∑ transition has a much higher transition dipole moment than the 1~3Π-X~3∑~- transition even though the l~3Π state is much lower in energy than the 2~3∑~- state.     

Low-lying excited states and photodissociation studies of cis-BrONO

A computational study of the low-lying singlet and triplet states of bromine nitrite, cis-BrONO, is presented. Calculations of excitation energies and oscillator strengths are reported using multi-reference configuration interaction, MRD-CI, methods in conjunction with the cc-pVDZ?+?sp and cc-pVTZ?+?sp basis sets. In agreement with recent experimental work the calculations find two important transitions, namely to the states 2¹ A′ at 3.99?eV and 4¹ A′ at 5.27?eV. The corresponding measurements obtained 3.87 and 5.44?eV, respectively. Both states show multi-reference character, representing a linear combination of 3a″?→?4a″ and 9a′?→?10a′ transitions. The potential energy curves for the Br+ONO dissociation are repulsive for both states indicating possible photodissociation. BrO+NO products are not favoured because the corresponding potential energy curves show barriers on the order of 0.5?eV.     

Low-lying electronic states of LiF molecule with inner electrons correlation

The potential energy curves and dipole moments of the low-lying electronic states of LiF molecule are performed by using highly accurate multi-reference configuration interaction with Awcv5z basis sets. 1s, the inner shell of Li is considered as the closed orbit, which is used to characterise the spectroscopic properties of a manifold of singlet and triplet states. 16 electronic states correlate with two lowest dissociation channels Li(²S)+F(²P) and Li(²P)+F(²P) are investigated. Spectroscopic parameters of the ground state X¹Σ⁺ have been evaluated and critically compared with the available experimental values and the other theoretical data. However, spectroscopic parameters of 1³Π, 1¹Δ, 1¹Σ^?, 1¹Π, 1³Σ⁺, 2³Σ⁺, 1³Δ, 1³Σ^?, 2³Π, 2¹Π, 3³Π, 3¹Π and 3³Σ⁺ states are studied for the first time. These 13 excited states have shallow potential wells, and the dispersion coefficients of these excited states are predicted. In additional, oscillator strengths of excited states at equilibrium distances are also predicted.     

Low-lying electronic states of BeH+ with the effect of inner electrons

The potential energy curves of the low-lying electronic states of BeH⁺ molecular ion are performed by using highly accurate multi-reference configuration interaction with AV5Z basis sets for H atom and ACV5Z basis set for Be atom, 1s inner shell of Be is considered as the core orbit and the active orbit, respectively, which are used to characterise the spectroscopic properties of a manifold of singlet and triplet states. Fourteen electronic states correlated with eight dissociation channels are investigated, we have found that the a³Σ⁺ and c³Σ⁺ both are bound states, the 3³Σ⁺ possesses double wells, and the C¹Σ⁺, 3³Σ⁺, 2³Π, 2¹Π, 1¹Δ, 1³Δ, 2³Δ and 2¹Δ states are studied for the first time. Transition dipole moment, Franck–Condon factors q_υ′υ^″ and Einstein coefficients A_υ′υ^″ for A¹Σ⁺–X¹Σ⁺, 2¹Π–B¹Π, c³Σ⁺–a³Σ⁺ and b³Π–a³Σ⁺ systems have been calculated. Radiative lifetime of A¹Σ⁺–X¹Σ⁺ band system has also been determined.     

Low-lying states in112In

Low-lying states below 500 keV excitation in¹¹²In have been investigated via the¹¹²Cd(p, nγ) reaction. New levels have been established atE ^x=206.5keV and 456.1 keV from the measuredγ-ray excitation functions,γ?γ coincidences and the precision measurements of the (p, n) threshold energy of the ground state and of the 206.5 keV state of¹¹²In. Spins and parities of the 206.5 keV state (2⁺) and the 456.1 keV state (3⁺) and multipolarities and mixing ratios of the deexcitationγ-rays have been determined from the angular distributions and linear polarizations of the deexcitation γ-rays as well as the excitation functions of the residual levels. Possible configurations of the newly-found levels are discussed. Half-lives of two states have been remeasured:T _1/2=15.2±0.1 min for the ground state andT _1/2=20.9±0.1 min for the 156.4 keV (4⁺) state. The ground stateQ-value for the¹¹²Cd(p, n)¹¹² In reaction has been measured to be ?3.376±0.006 MeV.     

Low-lying states of F2 +

Calculated potential energy curves for the 13 lowest electronic states of F₂ ⁺ are presented. Nine of the potential curves are found to possess substantial binding energies, while two others also display shallow, stable minima. The ordering, binding energies, relative equilibrium separations and vibrational frequencies of these curves should be of utility in helping to assign the large number of observed vibration-rotation lines in the electronic emission spectrum of F₂ ⁺. The calculated curves are in reasonable agreement with the available data on the two experimentally observed states.     

Low-lying vibrational states of145,147,149Nd

The fragmented neutron states in^145,147,149Nd detected through¹⁴⁴Nd(d, p) and^148,150Nd(d, t) reactions can be accounted for in terms of quasiparticles coupled with anharmonic vibrator model. The wave functions, obtained from diagonalisation of the Hamiltonian matrices are utilised to calculate B(E2), B(M1) and branching ratios in^145,147Nd. The calculated results are discussed in the light of the recent experimental findings.     

Low-lying states and separabelized Skyrme interactions

A finite-rank separable approximation for the quasiparticle RPA calculations with Skyrme interactions that was proposed in our previous work is extended to take into account the coupling between one-and two-phonon terms in the wave functions of excited states. It is shown that the phonon-phonon coupling effect can be very important to reproduce experimental data.     

Low-lying states of the102Rh nucleus

Zeitschrift für Physik A Hadrons and nuclei - The reaction32S+126Te has been used to determine theg-factor of theT 1/2=35 ns yrast isomeric state in154Er through the time-differential...     

Low-lying two-particle states in the nucleus236Np

The ambiguities and the uncertainties about the energy levels of the doubly odd actinide nucleus ₉₃ ²³⁶ Np₁₄₃ are sought to be removed by determination of the bandhead energies of various two-particle configurations expected to appear in the low energy spectrum of this nucleus. The calculations involve quantitative evaluation of the zero range neutron-proton residual interaction energy contribution to the bandhead energy for each configuration. It is concluded that the ground state is the long-lived isomer with spin-parityI ^π=6^- arising from the configuration {5/2⁺[642] _p +7/2^?[743] _n }. Bandhead energies for eight two-particle states appearing upto an excitation energy of 400 keV are presented and the results are discussed in the context of the available and further experiments.     

Low-lying nuclear deformed states and angular momentum projection

A fast computational method for approximate angular momentum projection is proposed for low-lying deformed nuclear states. The accuracy of the method is demonstrated by calculating the low-lying states of the ground-state band and the two 0⁺ excited bands in ¹⁶⁸Er with good experimental comparison.     

MRCI study on spectroscopic and molecular properties of four low-lying electronic states of the BO radical

The potential energy curves (PECs) of four low-lying electronic states of the BO radical, including two ²Σ⁺ and two ²Π states, have been studied using the full valence complete active space self-consistent field (CASSCF) method followed by the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in combination with the cc-pV5Z basis set for internuclear separations from 0.05 to 2.0 nm. The effect on the PECs by the relativistic correction has been taken into account. With these PECs, the spectroscopic parameters (T_e, D₀, D_e, R_e, ω_e, ω_ex_e, α_e and B_e) of two main isotopologues (¹¹B¹⁶O and ¹⁰B¹⁶O) have been determined. These parameters have been compared in detail with those of previous investigations reported in the literature, and excellent agreement has been found between the available data and the present results. By solving the radial Schrödinger equation of nuclear motion, 60 vibrational states for the ¹¹B¹⁶O(X²Σ⁺), 60 for the ¹⁰B¹⁶O(X²Σ⁺), 66 for the ¹¹B¹⁶O(A²Π) and 64 for the ¹⁰B¹⁶O(A²Π) are predicted for the non-rotating molecule. For each vibrational state of the ¹¹B¹⁶O(X²Σ⁺), ¹⁰B¹⁶O(X²Σ⁺), ¹¹B¹⁶O(A²Π) and ¹⁰B¹⁶O(A²Π), the vibrational level G(υ), inertial rotation constant B_υ and centrifugal distortion constant D_υ have been determined. Comparison with the available data shows that the present molecular constants are reliable and accurate. The ro-vibrational levels have been calculated for the X²Σ⁺ and A²Π states of two main species for future laboratory research.