Electronic collision: Induced transition between the upper levels of a He–Cd laser

Interruption of the laser field in a 4416-Å He–Cd laser modulates the spontaneous emissions originating not only from the laser levels but also from other excited levels. From the measurement of the intensity ratio of these spontaneous emissions, the rate coefficient of the transition between 4d9 5s2 configurations in Cd II induced by electronic collision and its cross section are obtained. The total deexcitation rate of the level by electronic collision is also measured.