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Determination of appearance energy for ions formed in the gaseous phase over alkali iodide and rare earth iodide systems
Author(s) -
Popovič A.,
Muhič S.,
Marsel J.,
Ajtony Zs.,
Bencze L.,
Kaposi O.,
Zmbov K. F.
Publication year - 1989
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1290030702
Subject(s) - chemistry , ion , iodide , analytical chemistry (journal) , alkali metal , ionization , extrapolation , mass spectrometry , phase (matter) , ionization energy , evaporation , chemical ionization , thermodynamics , inorganic chemistry , chromatography , organic chemistry , mathematical analysis , physics , mathematics
Knudsen cell mass spectrometric measurements are reported on the composition of vapour over solid and fused NaI, CsI, HoI 3 , DyI 3 , (NaI + HoI 3 ), (NaI + DyI 3 , (CsI + HoI 3 ) and (CsI + DyI 3 systems. For the determination of evaporation thermodynamics, the assignment of the essential ions to their neutral precursors was carried out by determining ionization efficiency curves. Due to the spread in electron energy, the linear extrapolation and vanishing current methods, which are generally used in high temperature mass spectrometry for evaluation of efficiency curves, could be used with limitations only. The analytical energy‐distribution difference method was used to determine the fine structure of the ionization efficiency curves. The method uncovered relationships between the detected ions and neutral vapour‐phase species, and served to determine thermodynamic data with improved precision.