Somogyi Wilfrid, Yurchenko Sergey N, Kim Gap-Sue
Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT London, UK.
Dharma College, Dongguk University, 30, Pildong-ro 1-gil, Jung-gu, Seoul 04620, Korea.
Phys Chem Chem Phys. 2024 Nov 7;26(43):27419-27430. doi: 10.1039/d4cp02619e.
We present a unified variational treatment of the magnetic dipole matrix elements, Einstein coefficients and line strength for general open-shell diatomic molecules in the general purpose diatomic code Duo. Building on previous work in which similar expressions for the electric quadrupole transitions were developed, we also present a complete spectroscopic model for the infrared, electric dipole-forbidden, spectrum of the O molecule. The model covers seven states, namely the X Σ-g, a Δ, b Σ+g, I Π, II Π, I Π and II Π states, for which 7 potential energy, 6 electronic angular momentum, 7 spin-orbit, and 14 quadrupole moment curves are calculated using ic-MRCI theory and an aug-cc-pV5Z basis set. These curves are diabatised to remove avoided crossings between the excited Π states, and the resultant properties are used to produce a line list for higher-order transitions of astrophysical interest.
