Line lists for the X2Σ+-X2Σ+, A2Π-A2Π and A2Π-X2Σ+transitions of CP

Rovibrational energy levels of CP are investigated for its X-2 Sigma(+) and A(2)Pi electronic states. Rovibronic frequencies observed experimentally for the A(2)Pi-X-2 Sigma(+) transition are used to produce empirical energy levels with the MARVEL method (denoted as MARVEL energy levels). The MARVEL energy levels for the X-2 Sigma(+) and A(2)Pi states are then employed to fit the empirical potential energy curves (PECs), spin orbit coupling curves (SOCCs) and electronic angular momentum curves (EAMCs) by using the DUO program, also constrained by the corresponding ab initio curves. Meanwhile, empirical Born-Oppenheimer breakdown curves, spin-rotation curves (SRCs), A-doubling curves are also added to well reproduce the MARVEL energy levels. These curves referred to as analytical spectroscopic models are as an input to DUO to obtain the fitted energy levels for the X-2 Sigma(+) and A(2)Pi states and the line lists for the X-2 Sigma(+)-X-2 Sigma(+), A(2)Pi-A(2)Pi and A(2)Pi-X-2 Sigma(+) transitions. Partition functions for temperatures up to 5000 K are computed by using the fitted energy levels and fitted by polynomial expansions. The calculated MARVEL energies can be used for spectroscopic investigations of the interstellar CP radical in various astrophysical sources, especially in circumstellar envelopes and warm clouds. The rovibrational energy levels and line lists derived from the analytical spectroscopic models can be used for predicting spectroscopy at temperatures up to 5000 K for potential applications in related plasmas. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study investigates the rovibrational energy levels and line lists of the CP molecule in different electronic states by combining experimental observations and theoretical calculations. The MARVEL method is used to generate empirical energy levels, which are then fitted using the DUO program to obtain various rovibrational energy levels and corresponding line lists, providing a data basis for further spectroscopic research.