Knowledge Bank

The only known example of hyperfine predissociation occurs in the $I2$ molecule. It has been extensively studied (1). Observation of a similar effect in $Br2$ is hindered by a strong rotational predissociation $(\alpha J(J+1))$ but the longer radiative lifetime of $B3\Pi Ou+$ state of $Br2$ favors its detection at low J (1). With a supersonic $Br2$ beam the populations of low J values is enhanced. The excitation spectrum is obtained at $\sim$ 1 MHz resolution. The hyperfine structure of various lines display strong intensity anomalies. From the relations given in (1) we were able to determine the radiative lifetime and rotational and hyperfine predissociation parameters for some levels of the $B3\Pi Ou+$ state of $Br2$