A quantitative time-of-flight secondary ion mass spectrometry study of ion formation mechanisms using acid-base alternating Langmuir-Blodgett films
Abstract
The effect of pre-existing acid-base proton transfer on ion formation in secondary ion mass spectrometry (SIMS) is studied with model systems constructed by Langmuir-Blodgett techniques. Reflection-Absorption FTIR was used to verify proton transfer in tri-layer LB assemblies of docosanoic acid (A) and 1-docosylamine (B). A recently developed quantitative method for quasi-molecular ions in Static SIMS was extended to Time-of-Flight SIMS. The formation of protonated base ions ((B + H) +) is highly dependent on film structure and pre-existing chemistry. The formation of the conjugate (A-H) -) carboxylate anion is more dependent on concentration of species rather than local chemistry. The implications for molecular quantitative analysis in SIMS are discussed.
- Publication:
-
Applied Surface Science
- Pub Date:
- October 1995
- DOI:
- 10.1016/0169-4332(95)00055-0
- Bibcode:
- 1995ApSS...90..205L