A generalized thermodynamic model for thermochemical processes in a direct-current arc discharge with vaporization of a sample from both the surface and the crater of the electrode is developed. This model is based on partitioning a nonsteady nonequilibrium thermodynamic arc-discharge system into consecutive, locally quasi-equilibrium subsystems corresponding to the stages of vaporization and thermochemical transformation of a sample in a discharge plasma. The model involves thermodynamic simulation of the gas-phase composition over the surface of the vaporized sample at the effective electrode temperature, passage to the initial composition of the arc-discharge plasma using the relationships obtained in this work, thermodynamic simulation of the composition of the arc-discharge plasma with regard to ionization processes, and calculation of the intensities of particular lines of atoms and ions. The validity of the generalized model was confirmed by comparison with experimental data. © 1997 MAEe cyrillic signK Hayκa/Interperiodica Publishing.