A method is presented for the calculation of populations following an ionisation event of individual states of more than one degree of ionisation, in the sudden approximation, using only bound-state wavefunctions. It is applied to 1s ionisation on argon, where it is shown that single excitation is twice as probable as single ionisation from the outer shell, and doubly-excited or singly-excited singly-ionised states have nonnegligible populations. Relativistic effects are found to substantially mix states of different LS symmetry, so the monopole selection rules for shake-up/shake-off in LS coupling are not strictly obeyed.