Auger decay with shake

AD), Auger decay with shake-up (ASU), and double Auger decay (DAD). Auger decay also can be followed by cascade autoionization. 

PA = participant autoionization SA = spectator autoionization PDA = participant double autoionization, SDA = spectator double autoionization CA = cascade autoionization AD = Auger decay ASU = Augur decay with shake-up DAD = double Auger decay, ICD = interchannel decay. 

These studies later were extended to molecules containing only elements from the first series of the periodic table (Carlson and Krause 1972). For these molecules, with only two electronic shells, an Auger cascade cannot occur. Each K shell vacancy produced by x-ray ionization of a Is electron produces a single Auger event with the total loss of two valence electrons. Additional electrons can be lost in shake-off ionization and double Auger decay, which were estimated to contribute about 20% to the the observed ion yields. 

As has been described, the creation and relaxation of a core hole excited state involving shake-up, shake-off, and single and multiple electron autoionization and Auger decay, generally leaves the system with two or more holes in bonding orbitals, which essentially means that bond has disappeared and often the system is left on a repulsive potential curve. The importance of such multiple-electron excited states has been discussed for bond rupture and desorption for covalently bonded species (Ramaker 1983a, b,c Madey et al. 1981 Jaeger et al. 1982 Treichler et al. 1985). 

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