2025MNRAS.536..714S

A new phosphorous mononitride ($^{31}$P$^{14}$N and ${}^{31}$P${}^{15}$N) line list PaiN covering infrared, visible, and ultraviolet regions is presented. The PaiN line list extending to the $A\, {}^{1}\Pi$-$X\, {}^{1}\Sigma ^{+}$ vibronic band system replaces the previous YYLT ExoMol line list for PN. A thorough analysis of high-resolution experimental spectra from the literature involving the $X\, {}^{1}\Sigma ^{+}$ and $A\, {}^{1}\Pi$ states is conducted, and many perturbations to the $A\, {}^{1}\Pi$ energies are considered as part of a comprehensive MARVEL (Measured-Active-Rotational-Vibrational-Energy-Levels) study. Ab initio potential energy and coupling curves from the previous work are refined by fitting their analytical representations to 1224 empirical energy levels determined using the MARVEL procedure. The PaiN line list is compared to previously observed spectra, recorded and calculated lifetimes, and previously calculated partition functions. The ab initio transition dipole moment curve for the A-X band is scaled to match experimentally measured lifetimes. The line list is suitable for temperatures up to 5000 K and wavelengths longer than 121 nm. PaiN is available from www.exomol.com.