Mass spectrometric study of the laser-produced carbon vapor up to 4500 K

The mass spectrometric measurements of the molecular composition in a carbon vapor produced by the laser induced sublimation of pyrolitic graphite have been carried out up to 4500 K, temperature that stands very close to the carbon's triple point. The measurements of the relative partial pressure of the dominant C-3 molecule up to the maximum temperature achieved did not deliver any unanticipated results, which could be attributed to any kind of the phase transitions. This has therefore indirectly confirmed that the temperature of the carbon triple point cannot be below 4500 K. The widely known problem of a significant deviation of evaporation coefficients of carbon molecules from unity has been largely addressed by a comparative analysis of the evaporation of two planes of pyrolitic graphite. The technical means that allowed for the mass spectrometric study of the carbon sublimation at extreme temperatures are further discussed in detail.