PHOTOABSORPTION SPECTRUM OF MG I IN THE RANGE 226-170 A (54-70 EV)

The photoabsorption spectrum of Mgi has been observed in the spectral region 226-170 A (54-70 eV) using synchrotron radiation as a background source. The one-electron excitation levels associated with the series: 1s**22s**22p**63s**2**1S//O yields 1s**22s**22p**5 left bracket **2P//3/////2//,//1/////2 right bracket 3s**2ns, nd were observed as well as 29 two- and three-electron excitation resonances. A critical analysis of the one-electron excitation spectrum was made and classifications for all the multiple electron excitations have been suggested on the basis of their quantum defects to known limits in Mgii.