A method of dispensing mercury into an arc discharge lamp containing a mercury capsule adjacent one of the coil electrodes is disclosed. The method includes the step of preparing a solution of a low ionization energy material and coating at least a portion of the mercury capsule. Thereafter, the mercury dispensing capsule is bombarded with a directed stream of electrons produced by the other coil electrode of sufficient energy to rupture the capsule causing the mercury to be released. The coating focuses the directed stream of electrons directly on the capsule, thereby reducing the amount of time necessary to rupture the capsule.