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By using the multireference configuration interaction method followed by Davidson correction, the electronic structure of the molecule CaI has been investigated. The potential energy curves, the permanent and transition dipole moment curves, and the spectroscopic parameters of 18 electronic states are investigated for these states, along with 111 vibrational levels of the four lowest electronic states. The Franck–Condon factors and the radiative lifetime are calculated for the X2Σ+–(1)2Π transition. For this transition, the vibrational branching ratio, the slowing distance L, and the number of cycles ( N) for photon absorption/emission are calculated along with the Doppler and the recoil temperatures. A pre-cooling temperature in a helium buffer gas is studied and a laser cooling scheme is presented. The calculation of these different experimental parameters is crucial to exploring the optimal conditions under which the laser cooling experiment of CaI molecule will be performed.

For the alkali iodide molecules LiI, NaI, KI, and RbI, ab initio CASSCF/(MRCI+Q) calculations have been employed to investigate the adiabatic potential energy curves and the static dipole moment curves of the low-lying singlet and triplet electronic states in the representation 2S+1Λ(+/−). The spectroscopic constants Te, Re, ωe, Be, αe, the dipole moment μe, and the dissociation energies De have been computed for the bound states. Additionally, the percentage ionic character fionic around the equilibrium position of the ground state and the (2)1Σ+ state has been estimated. Using the canonical function approach, these calculations have been followed by a rovibrational calculation from which the rovibrational constants Ev, Bv, Dv, and the abscissas of the turning points Rmin and Rmax for the investigated bound states are calculated.

We investigate an orderly study of the adiabatic potential energy curves for 29 and 30 low-lying 2s+1Λ+/− electronic states of the molecules MgLi and MgNa, respectively. The calculation has been done by using the complete active space self-consistent field followed by multi-reference configuration interaction with Davidson correction. For the investigated electronic states, the static and transition dipole moment curves are calculated along with the Einstein coefficients, the emission oscillator strength, the spontaneous radiative lifetime, the line strength, the classical radiative decay rate of the single-electron oscillator, the spectroscopic constants (Te, ωe, ωexe, Be, Re), and the equilibrium dissociation energy De. By means of the canonical functions approach, the ro-vibrational constants Ev, Bv, Dv, and the abscissas of the turning points, Rmin and Rmax, have been calculated for the considered electronic states up to the vibrational level v = 79. The Franck–Condon factors have been calculated and plotted for the transition between the low-lying electronic states of the two considered molecules. A good agreement is revealed between our calculated values and those available in the literature. Fifty new electronic states are investigated in the present work for the first time.

Ab initio calculations have been applied to investigate the electronic structure of the SrO molecule. The potential energy curves have been computed in the Born–Oppenheimer approximation for the ground, and the 29 low-lying singlet and triplet excited electronic states. Complete active space self-consistent field, multi-reference configuration interaction have been utilized to investigate these states. The harmonic frequency ωe, the internuclear distance Re, the rotational constant Be, and the electronic energy with respect to the ground state Te have been calculated by using two different techniques of calculation with different bases. The transition dipole moment between some doublet states is used to determine the Einstein spontaneous A21 and induced emission B 21 ω coefficients as well as the spontaneous radiative lifetime τspon, emission wavelength λ21 and oscillator strength f21. The eigenvalues Ev, the rotational constant Bv, the centrifugal distortion constant Dv, and the abscissas of the turning ...

The potential energy curves have been investigated for the lowest 54 electronic states in the [Formula: see text] representation of the molecule NaHe via the multireference configuration interaction method (MRCI) and second-order multireference perturbation theory (RPST2-RS2). The harmonic vibrational frequency, ωe, the internuclear distance, Re, the electronic energy with respect to the ground state, Te, and the permanent dipole moment, μ, have been calculated. The positions of Rmin and Rmax and their minimum and maximum energies Emin and Emax with respect to the dissociation asymptote have been determined for the considered electronic states. The comparison of our investigated values to the theoretical and experimental data available in the literature shows a good agreement. Forty-three electronic states have been studied theoretically in the present work for the first time.

The potential energy curves of the low-lying doublet electronic states in the representation 2s+1Λ(+/−) of the SrF molecule have been investigated by using the complete active space self-consistent field with multireference configuration interaction and multireference Rayleigh–Schrödinger perturbation theory methods. The harmonic frequency, ωe; the internuclear distance, Re; the dipole moment; and the electronic energy with respect to the ground state, Te, have been calculated for the considered electronic states. The eigenvalues, Ev; the rotational constants, Bv; and the abscissas of the turning points, Rmin and Rmax, have been investigated using the canonical functions approach. The comparison between the values of the present work and those available in the literature for several electronic states shows very good agreement. Nine new electronic states have been investigated here for the first time.

The potential energy curves of the molecule LiCs have been calculated for the 55 low-lying electronic states in the Ω-representation. Using an ab initio method the calculation is based on a nonempirical pseudo-potential in the interval 3.0ao≤ R ≤ 40.0ao of the internuclear distance. The spin–orbit effects have been taken into account through a semi-empirical spin–orbit pseudo-potential added to the electrostatic Hamiltonian with Gaussian basis sets for both atoms. The spectroscopic constants have been calculated for 39 states and the components of the spin–orbit splitting have been identified for the states (2, 5)3Π and (1)3Δ. The comparison of the present results with those available in literature shows good agreement, while the other results, to the best of our knowledge, are given here for the first time.

For the molecular ion LiCs+ the potential energy are calculated for the 39 lowest molecular states of symmetries 2Σ+, 2Π, 2Δ, and Ω = 1/2, 3/2, 5/2. Using an ab initio method, the calculation is based on nonempirical pseudopotentials and parameterized [Formula: see text]-dependent polarization potentials. Gaussian basis sets are used for both atoms and spin-orbit effects are taken into account. The spectroscopic constants for 20 states are calculated by fitting the calculated energy values to a polynomial in terms of the internuclear distance r. Through the canonical functions approach, the eigenvalue Ev, the abscissas of the corresponding turning points (rmin and rmax), and the rotational constants Bv are calculated for up to 44 vibrational levels for four bound states. Using the same approach the dipole moment functions, the corresponding matrix elements, and the transition dipole moments are calculated for the bound states (1)2Σ+, (2)2Σ+, and (1)2Π. The comparison of the present results with those available in literature for the ground state shows a very good agreement. Extensive tables of energy values versus internuclear distance are displayed at the following address: http://lasim.univ-lyon1.fr/allouche/licsso.html.PACS Nos.: 31.15.Ar, 31.25.–v, 31.25.Nj

For the transitions a a in the Rayleigh-Schrodinger perturbation theory, the rovibrational wave function is written in terms of the running number 6 as ' S 6 where 6 'd a E a nA 3 a E an Ao*2 ,a nd are new functions that can be obtained easily from the rotation harmonics defined in perturbation theory. By using this "6-representation" of the wave function we obtained the rovibrational matrix elements as  '  C E6 where the rotational factor is given by C E6 ' S 6 . The coefficients are simple combinations of integrals of the form E s E :and E :even for the high-order coefficients (up to the fourth order). These results are valid only in the case of the P electronic state for any potential (either analytical or numerical), any vibrational level (even near dissociation), and any operator s . The numerical application to the ground state of the molecule CO shows the high degree of accuracy of the present formulation with a simple algorithm and simple analysis tools. R´

The matrix elements of the polarizability anisotropy γ in the Raman spectra of diatomic molecules are investigated. These matrix elements are given by [Formula: see text] where Gνν′(m) is the rotational factor with m = [(J′(J′ + 1) − J(J + 1)]/2 and J′ − J = ±2. By using a nonconventional approach to the Rayleigh–Schrödinger perturbation theory the rotational factor can be written as Gνν′(m) = A0 + A1m + A2m2 where the coefficients A0, A1, and A2 are given by simple analytical expressions in terms of the integrals [Formula: see text] and [Formula: see text] where Y stands for Ψ(0) (the pure vibration wave function), or Ψ(0) (the first rotational perturbative correction to Ψ(0), or Ψ(2) (the second correction). A numerical application is presented for the ground states of CO and H2 molecules. A comparison with a numerical and direct calculation of the rotational factor Gνν′(m) shows the accuracy of the present formalism.