Diamond stands out among single-photon sources due to an intrinsically large band
gap, photo-stable emission, room-temperature operation, short excited state
lifetimes, and the ability to host hundreds of different color centers.
Currently, most of these centers are active in the optical spectrum, but a
single-photon source in the infrared would represent a significant advancement.
In pursuit of this end, a number of different transition metal atoms have been
studied as dopants in the diamond lattice via the GAMESS (General Atomic
Molecular and Electronic Structure System) cluster calculation package. The
importance of cluster size and electron correlation effects is considered, and
excitation energies have been calculated via time-dependent density functional
theory.