Ionisation energy, adiabatic

The smaller cluster ions 83", 84" and 85 + have been examined by Zakrzewski and von Niessen at the HF/6-3H-G level [82]. The lowest cationic states are predicted to be 82, and A" for 83 (Cyv), 84 (I>4h) and (Cs), respectively. The ionisation processes may result in significant structural relaxation leading to the sequence of states different from that of the vertical states. The calculated lowest adiabatic ionisation energies, using the GI method with a very large ANO basis set, are 9.53, 8.05, and 8.20 eV for 83, 84 and 85 , respectively. 

IE,IP) ionisation potential. Compare with adiabatic ionisation energy, vertical ionisation energy, electronegativity, and electron affinity. The energy needed to remove an electron from a gaseous atom or ion. 

The vertical ionisation energy is the energy required to form the positive ion with the same geometry as the ground state molecule. In the adiabatic ionisation energy, the positive ion is formed in its thermally-relaxed vibrational ground state (see Fig. 1.23)... 

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