Knowledge Bank

Codeposition of $O2$ with the superheated vapors of selenium from a Knudsen cell yields $Se2O2$, with bonds at 1404, 391 and $361cm-1$. The presence of the $O2$ fragment is confirmed by scrambled 0-16/0-18 experiments; a triplet with very narrow lines, is obtained, suggesting that the two oxygens are equivalent and/or poorly vibrationally coupled to the $Se2$ moiety. The presence of the $Se2$ fragment is suggested by the locations of the observed bands, the subsequent chemistry in the matrix, and the correspondence with the sulfur-oxygen system, in which $S2O2$ is found. Subsequent photolysis at $\lambda >490$ nm yields SeO ($883cm-1$) $(SeO)2$ (the vander Waals dimer, $875cm-1)$, $SeO2-Se$ (perturbed $SeO2$, 960, 921, $365cm-1$), and SeOSeO (966, 636, and $294cm-1$). In each of these product molecules, the individual lines due to the selenium isotopes, occurring in natural abundance, were resolved. Codeposition of $O3$ with the superheated selenium vapors yields, in addition to SeO, a broad band which is assigned to $Se2O(903cm-1$); this feature is also obtained when one traps the products of a microwave discharge in argon seeded with oxygen and selenium vapor.