Thermochemical heat of ablation of solid carbon

The thermochemical heat of ablation of carbon, HA, is usually set equal to 32 kJ/g as derived from the JANAF tables. There is, however, some uncertainty since JANAF-recommended values for heats of vaporization and partial vapor pressures differ from the results of a detailed analysis that was carried out at the Lawrence Livermore National Laboratory (LLNL). We find that the LLNL model yields carbon-vaporization enthalpies that are appreciably lower than the JANAF-based values. In this light, we examine experimental data generated in the course of a comprehensive investigation of laser-interaction effects in graphite and conclude that our experiments are indicative of an HA equal to 31.0±1.6 kJ/g.