It. Cheon, MODIFICATION OF THE TRANSITION RATE IN THE HYDROGEN-ATOM PLACED IN FINITE SPACE, Zeitschrift fur Physik. D, Atoms, molecules and clusters, 39(1), 1997, pp. 3-8
When a hydrogen atom trapped in finite space formed by two parallel pe
rfectly conducting plates, the transition rates can be modified. Life-
time of the hydrogen 2P(1/2)-state is estimated to be shorter as much
as 56.3ps with a separation distance of b = 1.2 mu m between two plate
s. Although the modification is dependent on position of the atom, the
life-time can be shorten or lengthen by adjusting the separation dist
ance even for the case that the atom is placed at the center between t
wo plates.