Methodological improvements in the multiple Knudsen cell mass spectrometry Original Research Article

Knudsen effusion cells coupled with mass spectrometry are used to determine thermodynamic data of gaseous and condensed phases. The need for determination of activities in condensed systems led to the design of a so-called ‘multiple effusion cell’ device. This new technique requires some methodological efforts and special prerequisites which have been integrated in a new device. This one is essentially characterized with an accurate positioning device attached directly to the mass spectrometer in conjunction with a restricted collimation of the effused molecular flow. Beyond the determination of reliable and accurate activities, evaporation and condensation coefficients can also be determined.