Spectroscopoc Properties About Loy-lyingelectronic States Of BO Radical And NF~+ Cation

From the molecular potential energy function, we can obtain a great variety of molecular properties(such as, mechanical properties, geometric properties, spectrum properties, chemical properties and so on). However, the potential energy function of the diatomic molecule is regarded as the basic issues. Because it is only the function of the internuclear distance between two atoms. Molecular potential energy curves(PECs) and its analytical form are one of the important research branches in atomic and molecular physics, and it is also the foundation of atom molecule collision and molecule reaction kinetics. In the present work, the PECs, spectroscopic parameters and transition properties for two diatomic molecules or cation(BO and NF+) are calculated. The effects on the spectroscopic parameters by some corrections are considered.For our first work of this paper, the spectroscopic properties of 23 Ω states generated from the 13 Λ-S states of BO radical are studied for the first time for internuclear separations from about 0.07 to 1.0 nm. Of the 13 Λ-S states, each of the F2Π, 12Φ and 12Δ states is found to possess the double well. Each of the 14Π, C2Π, 12Σ- and 22Σ- states possesses one well with one barrier. The A2Π, 14Π and F2Π are the inverted states with the spin-orbit coupling effect taken into account. All the states possess the deep well except for the 12Φ. The Franck-Condon factors and radiative lifetimes of the transitions from the B2Σ+, C2Π, D2Σ+, 12Σ-and 14Π Λ-S states to the ground state are calculated for several low vibrational levels. The second work of this paper studies the PECs of 27 Ω states generated from the 12 Λ-S states, which are attributed to the first dissociation channel of NF+ cation. Of these 12 states, only the 22Σ- and 24Π are the repulsive ones. In addition, the 12Δ and 14Σ- states are found to possess the double well. The 14Σ+, 14Σ- and 14Δ are found to be the inverted states with the spin-orbit coupling effect taken into account. And the 12Σ+, 12Σ-, 12Δ, 14Σ+, 24Σ- and 14Δ are found to be the weakly bound states. The Franck-Condon factors and radiative lifetimes of the transitions from the 14Π3/2, 14Σ-3/2, 12Δ3/2 and A2Π1/2 states to the X2Π1/2 state are calculated for several low vibrational levels.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 behavior 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.On the whole, as can be seen from the comparison between the present results and the experiments, the Davidson, core-valence correlation, scalar relativistic corrections SO coupling effect and the energy extrapolation surely increase the spectroscopic parameters accuracy. The transition properties of diatomic molecules are studied which should be good references for future experimental or theoretical research.