Configuration interaction calculations of miscellaneous properties of the X²Pi_rground state, the C´²Delta excited state and related C´²Delta-X²Pi_rtransition bands of PO: I. X²Pi_rground state

Abstract

Extended basis set configuration interaction calculations on the ground state (X 2 r ) of PO have been performed. A wide variety of molecular properties are reported, including: (i) spectroscopic constants; (ii) vibrational energies and anharmonicity effects; (iii) pure rotational transitions for several (J , J ) sets and the first 11 vibrational quantum numbers; (iv) one-electron properties such as the electric dipole/quadrupole moments, nuclear quadrupole ( 17 O) coupling, anisotropic hyperfine parameters, etc; (v) vibrational electric dipole moments µ v ; (vi) cascade 2 r vibrational and rovibrational lifetimes. Good agreement is obtained with the available limited amount of experimental data. Finally, the accuracy of the present results is discussed and compared to that obtained for the CP(X 2 + ) state.

Multireference configuration interaction study on spectroscopic parameters and molecular constants of PO and PO+

“…By comparison with the experiments, it is easy to find that their accuracy is inferior to the presents expect for ω e of b 4 Σ − and C 2 Σ − with respect to PO. The same MRCI+Q method was adopted by de Brouckère52 to calculate the ground state properties of PO with aug‐cc‐pVQZ basis set. From Table I, it is not difficult to find that the values of B e and α e are still smaller than the experiments11.…”

“…In theory, a number of ab initio calculations were performed on the low‐lying electronic states of PO and PO + 39–56. However, the extracted spectroscopic properties from the theoretical work mainly focus on the spectroscopic parameters ( D e , R e , ω e , ω e χ e , α e , B e ).…”

Ab initio investigation of the ground state properties of PO, PO+, and PO−

“…A brief history of the experimental work on PO is given by de Brouckère. 65 It is worth noting that PO is believed to exist in dense interstellar clouds although evidence of its presence there is not yet conclusive. 48 In contrast to the experimental work, the theoretical investigation of these species has not been extensive.…”

“…48 In contrast to the experimental work, the theoretical investigation of these species has not been extensive. [52][53][54][55][56][57][58][59][60][61][62][63][64][65][66] The first calculations on PO and its anion were done as early as 1966 by Boyd and Lipscomb 52 at the self-consistent field/ Slater type orbitals ͑SCF/STO͒ level, and their results for the PO Ϫ were the only ones available for some time. In 1971 Mulliken and Liu 53 repeated the calculations on PO at the SCF/STO level with a larger basis set as part of their investigation of the importance of the d and f functions in the chemical bond.…”

“…In the MRCI calculations the correlation consistent cc-pVQZ basis set was employed. In the same year, a study of many properties of the ground state of PO was carried out by de Brouckère 65 at the MRCI and MRCI plus Davidson correction ͑ϭϩQ͒ levels using the aug-cc-pVQZ basis set and the MELDF-X package. Finally, in 2001 a study of multipole moments and dipole polarizabilities of the ground state of PO ϩ was carried out by Martin and Fehér 66 at the CASSCF level with a ͓9s6 p3d1 f ͔ basis set on P and a ͓8s6 p3d1 f ͔ basis set on O using the GAMESS program.…”