z 0 grows exponentially with an increase in ε HOMO and ε LUMO (Figure ). Quite far from the z 0 (ε HOMO ) dependence are only TMA + , EMPyr + and PyMe + . The alkali metal cations, H 3 O + , and EMI + fit quite well into the exponential dependence (Figure ), and all the ions considered fit into the linear z 0 (ε LUMO ) dependence (Figure ).