The absorption spectrum of calcium vapour: 1660-2028

The vacuum ultra-violet absorption spectrum of calcium vapour was observed in an attempt to discover transitions to new energy levels. Seven new levels have been found between 51 000 and 59 000 cm -1 , three of which are ascribed to the 3d5p, 3d6p and 5s4p configurations, with the remaining four lines resulting from transitions to 3d4f and 3d5f configurations. The 3d5p 3 P 1 0 level reported by Ditchburn and Hudson at 52 225 cm -1 is now found at 51 909 cm -1 . A graph of relative cross section for photoionization from the ground state of calcium is shown between 1660 Å and the principal series limit. A shock tube was used to observe several transitions to autoinizing levels from excited states.