TY - JOUR
T1 - Behavior of molecules and molecular ions near a field emitter
AU - Gault, Baptiste
AU - Saxey, David W.
AU - Ashton, Michael W.
AU - Sinnott, Susan B.
AU - Chiaramonti, Ann N.
AU - Moody, Michael P.
AU - Schreiber, Daniel K.
N1 - Funding Information:
BGacknowledges Shyeh Tjing (Cleo) Loi (University of Sydney) who performed theBEMsimulations, with support from Drs Brian Geiser&Drs David Larson (Cameca).Dr Frederic De Geuser (CNRS, UJF, France) is acknowledged for fruitful discussions and commenting on the manuscript. Dr Lan Yao (UMichigan) is thanked for providing the code to compute the Kingham curves. The Cambridge Centre of Gallium Nitride is acknowledged as the source of the material used in some of these analyses, for work has been funded, in part, by the EPSRC (GR/S 49391/01) and these atom probe analyses were performed at theUKAtom-probe Facility at the University of Oxford-funded by theUKEngineering and Physical Sciences Research Council (EPSRC) under grant no. EP/077664/1. DKS acknowledges support from the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated forDOEby Battelle. Lyle Gordon (PNNL) is acknowledged for providing the Fe3O4 sample described in this study.
Publisher Copyright:
© 2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.
PY - 2016/3/18
Y1 - 2016/3/18
N2 - The cold emission of particles from surfaces under intense electric fields is a process which underpins a variety of applications including atom probe tomography (APT), an analytical microscopy technique with near-atomic spatial resolution. Increasingly relying on fast laser pulsing to trigger the emission, APT experiments often incorporate the detection of molecular ions emitted from the specimen, in particular from covalently or ionically bonded materials. Notably, it has been proposed that neutral molecules can also be emitted during this process. However, this remains a contentious issue. To investigate the validity of this hypothesis, a careful review of the literature is combined with the development of new methods to treat experimental APT data, the modeling of ion trajectories, and the application of density-functional theory simulations to derive molecular ion energetics. It is shown that the direct thermal emission of neutral molecules is extremely unlikely. However, neutrals can still be formed in the course of an APT experiment by dissociation of metastable molecular ions.
AB - The cold emission of particles from surfaces under intense electric fields is a process which underpins a variety of applications including atom probe tomography (APT), an analytical microscopy technique with near-atomic spatial resolution. Increasingly relying on fast laser pulsing to trigger the emission, APT experiments often incorporate the detection of molecular ions emitted from the specimen, in particular from covalently or ionically bonded materials. Notably, it has been proposed that neutral molecules can also be emitted during this process. However, this remains a contentious issue. To investigate the validity of this hypothesis, a careful review of the literature is combined with the development of new methods to treat experimental APT data, the modeling of ion trajectories, and the application of density-functional theory simulations to derive molecular ion energetics. It is shown that the direct thermal emission of neutral molecules is extremely unlikely. However, neutrals can still be formed in the course of an APT experiment by dissociation of metastable molecular ions.
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U2 - 10.1088/1367-2630/18/3/033031
DO - 10.1088/1367-2630/18/3/033031
M3 - Article
AN - SCOPUS:84963701062
SN - 1367-2630
VL - 18
JO - New Journal of Physics
JF - New Journal of Physics
IS - 3
M1 - 033031
ER -