To be used with TDOutput = td_occup. Not available if TDOutput = populations.
Only output projections to states above TDProjStateStart. Usually one is only interested
in particle-hole projections around the HOMO, so there is no need to calculate (and store)
the projections of all TD states onto all static states. This sets a lower limit. The upper limit
is set by the number of states in the propagation and the number of unoccupied states
available.