Carbon K soft-x-ray emission spectra of LiC6, KC8, and CsC8 are presented. An absolute value for the charge transfer from the alkali metal to the carbon band is obtained. A model fit to the data reveals similar effects on both spectral shape and threshold energy, independent of the choice of the alkali-metal intercalant, and provides a measure of departures from the rigid-band approximation. An enhancement of the soft-x-ray emission spectrum near EF is reported. © 1987 The American Physical Society.