ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
To find the metal hydride best for producing H− by thermal desorption, the desorption rates of H−, H2 and electron (e−) directly emitted from a powdery sample (∼1 mg) of NaH, LiH, MgH2, CaH2, SrH2, TiH2, ZrH2, KBH4, LiAlH4, or NaAlH4 heated up to ∼1000 K were determined simultaneously with a special system. Theoretical analysis of the experimental data thus achieved yields the following results. (1) Both H− and e− are emitted from those active spots (mainly consisting of alkali or alkali earth metal) created by thermal decomposition (e.g., LiH→Li+H2/2). (2) The active spots are readily destroyed and reconstructed by admission of H2 and by stopping the admission, respectively. (3) The work function (φ) of activated NaH is very low (∼2 eV), but NaH is rapidly depleted owing to its thermal instability. (4) Among the ten hydrides, CaH2 is concluded to be the best as a source material for thermal desorption of H− because activated CaH2 (φ(similar, equals)5 eV) is most stable and strongest in H− (∼10−12 A or 10−10 A/cm2 after mass analysis) around 900 K. © 2000 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1150311
