The intriguing near-ultraviolet photochemistry of H2Te

The ultraviolet absorption spectrum of H2Te has a long wavelength tail that extends to 400 nm. Photodissociation at 355 nm yields TeH(2Π1/2) selectively relative to the 2Π3/2 ground state; the transition moments for these channels lie in, and perpendicular to, the molecular plane, respectively. Vibrational structure in the region 380–400 nm is consistent with a shallow well in the adiabat leading to 2Π1/2, akin to the one in HI leading to I(2P1/2). These effects have no counterparts with the light Group 6A dihydrides.