Electronic spectra of EuF studied by a four-component relativistic configuration interaction method

The addition of iron or boron and/or nitrogen, up to 20?%, to amorphous carbon with a density of about 2.0?gm/cm³ was studied using density functional theory. The bulk cohesive energy decreases with increasing iron, nitrogen, or boron concentration. The decrease is largest for iron and smallest for boron. The trends in the bulk moduli are consistent with the cohesive energies. The optical properties (absorbance and reflectivity) of the samples with nitrogen and/or boron added are very similar to those of the original amorphous carbon. Addition of iron results in larger, energy dependent, changes when compared with either boron or nitrogen. The effect of dopants on low-density amorphous carbon shows some differences with those for higher density amorphous carbon.