Laser-enhanced ionization studies of the blue satellite band in the Ca−Ar system associated with the electric-quadrupole transition 4 s 21 S 0 →4 s 3 d 1 D 2 of calcium

The collision-assisted electric-quadrupole transition 4s 21 S 0→4s3d 1 D 2 of calcium at 4575 Å has been observed using the laser-enhanced ionization technique for the first time. A blue satellite band due to the interaction of calcium 4s3d 1 D 2 state with argon1 S 0 has also been detected at 4527 Å which is shifted by 48 Å from the isolated atomic calcium line. The line broadening cross-section for the blue satellite has been calculated by measuring its collisional broadening at various argon pressures. Important processes involved in the generation of this blue satellite band are qualitatively discussed.