Spectral line

Quantum mechanics

Isotopologue

Metallurgy

Materials science

Ab initio quantum chemistry methods

Astrophysics

Energy (signal processing)

Atomic physics

Ab initio

Molecule

Titanium

Physics

Dipole

Mathematics

Astronomy

Geometry

Crystallography

Chemistry

Line (geometry)

Monthly Notices of the Royal Astronomical Society

Accurate line lists are crucial for correctly modelling a variety of astrophysical phenomena, including stellar photospheres and the atmospheres of extra-solar planets. This paper presents a new line database Toto for the main isotopologues of titanium oxide (TiO): $^{46}$Ti$^{16}$O, $^{47}$Ti$^{16}$O, $^{48}$Ti$^{16}$O, $^{49}$Ti$^{16}$O and $^{50}$Ti$^{16}$O. The TiO line list contains transitions with wave-numbers up to 30,000 cm$^{-1}$ ie long-wards of 0.33 $\mu$m. The Toto line list includes all dipole-allowed transitions between 13 low-lying electronic states (X $^3\Delta$, a $^1\Delta$, d $^1\Sigma^+$, E $^3\Pi$, A $^3\Phi$ B $^3\Pi$, C $^3\Delta$, b $^1\Pi$, c $^1\Phi$, f $^1\Delta$, e $^1\Sigma^+$). Ab initio potential energy curves (PECs) are computed at the icMRCI level and combined with spin-orbit and other coupling curves. These PECs and couplings are iteratively refined to match known empirical energy levels. Accurate line intensities are generated using ab initio dipole moment curves. The Toto line lists are appropriate for temperatures below 5000 K and contain 30 million transitions for TiO; it is made available in electronic form via the CDS data centre and via www.exomol.com. Tests of the line lists show greatly improved agreement with observed spectra for objects such as M-dwarfs GJ876 and GL581.

ExoMol molecular line lists – XXXIII. The spectrum of Titanium Oxide