  We have investigated the local density of optical states (LDOS) in titania
and silicon inverse opals -- three-dimensional photonic crystals that have been
realized experimentally. We used the H-field plane-wave expansion method to
calculate the density of states and the projected local optical density of
states, which are directly relevant for spontaneous emission dynamics and
strong coupling. We present the first quantitative analysis of the frequency
resolution and of the accuracy of the calculated local density of states. We
have calculated the projected LDOS for many different emitter positions in
inverse opals in order to supply a theoretical interpretation for recent
emission experiments and as reference results for future experiments and theory
by other workers. The results show that the LDOS in inverse opals strongly
depends on the crystal lattice parameter as well as on the position and
orientation of emitting dipoles.
