mptotic correction.  This is primarily intended
for use in conjunction with TDDFT and the background of this method is given in more
detail in Chapter 14.  The shift is normally positive (which means that the original
uncorrected exchange-correlation potential must be shifted down).

<P>
When the keyword <code>CS00</code> is specified without the value of shift, the program will
automatically supply it according to the semi-empirical formula of Zhan, Nichols, and
Dixon (again, see Chapter 14 for more detail