Theoretical Study on the Infrared and Ultraviolet Spectroscopy of PO+

Abstract

In this study, the potential energy function, dipole moment function, and transition dipole moment function of the PO⁺ are computed employing high-precision multi-reference configuration interaction methods. By solving the one-dimensional Schrödinger equation for the nuclei, vibrational and rotational energy levels of eight bound states are obtained, subsequently enabling the calculation of the partition function for the PO⁺ molecule. Combining the partition function with the dipole moment function and transition dipole moment function, spectral lines for the PO⁺ molecule in both the infrared and ultraviolet ranges are computed. The spectral lines in the infrared range primarily originate from vibrational-rotational transitions associated with the $X^1{\Sigma }^{+}$ state, while the spectral lines in the ultraviolet range mainly arise from transitions involving the $X^1{\Sigma }^{+}\leftrightarrow C^1\Pi$. At 296 K, the most intense spectral lines in the infrared range are generated by the 0–0 vibrational band($v^{\prime }=0,v^{″}=0$), while the most intense spectral lines in the ultraviolet range are produced by the 2–0 vibrational band($v^{\prime }=2,v^{″}=0$). At elevated temperatures, the overall intensity of spectral lines decreases as more energy levels are excited, and the central positions of spectral peaks undergo shifts. This study extensively computed the spectral line data for the PO⁺ molecule, providing crucial data support for astronomical observations.