The vapor pressure of potassium has been measured in absorption using a cw tunable laser and calibrated against the accurate radiative lifetime of the 4s—4p doublet of potassium. An accurate value of 20,850 ± 30 cal/mol for the heat of vaporization (from the liquid phase) at the melting point was determined.
© 1983 Optical Society of America
B. Shirinzadeh and Charles C. Wang, "Accurate determination of the vapor pressure of potassium using optical absorption," Appl. Opt. 22, 3265-3270 (1983)