Investigating the Fundamentals of Molecular Depth Profiling Using Strong-field Photoionization of Sputtered Neutrals.
Molecular depth profiles of model organic thin films were performed using a 40 keV C60+cluster ion source in concert with TOF-SIMS. Strong-field photoionization of intact neutral molecules sputtered by 40 keV C60+primary ions was used to analyze changes in the chemical environment of the guanine thin films as a function of ion fluence. Direct comparison of the secondary ion and neutral components of the molecular depth profiles yields valuable information about chemical damage accumulation as well as changes in the molecular ionization probability. An analytical protocol based on the erosion dynamics model is developed and evaluated using guanine and trehalose molecular secondary ion signals with and without comparable laser photoionization data.
Department of Chemistry, Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802.
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Willingham
Department of Chemistry, Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802.
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Brenes
Department of Chemistry, Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802.
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Winograd
Fachbereich Physik, Universitaet Duisburg-Essen, 47048 Duisburg, Germany.
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Wucher