Electrothermal at. absorption spectrometry is applied to study the release of the arsenic, antimony and bismuth atoms from pyrocoated graphite support. The influence of the chem. modifiers tungsten and palladium on the absorbance time profiles is exptl. evaluated. The Sturgeon's approach is used for estn. of the apparent activation energies of the atom release. The addn. of modifier leads to enhancement of the activation energies and changes the kind of the vaporizing species for analytes. The possible mechanisms of vaporization and atomization for As, Sb and Bi are discussed. [on SciFinder (R)]