The3p3Σ→2s3Σ-Bands of TH andT2

The molecular spectra of TH and ${\mathrm{T}}_2$ were photographed under high dispersion. The classification of the $3p^3\Sigma \to 2s^3\Sigma$-system is given for these two molecules as well as the molecular constants for the $3p^3\Sigma$-state. Irregularities in the structure including typical perturbations are accounted for by interaction with the $3p^3\Pi$-state. This system, with 58 known bands and more than 1150 classified lines, is now known considerably better for ${\mathrm{T}}_2$ than for any other species of hydrogen molecule, including ${\mathrm{H}}_2$.