Detection of Molecular-Surface Adsorbates at the 10(-6)-Monolayer Level and Below
Ultrathin molecular surface overlayers were deposited in an UHV chamber and were detected using pulsed infrared laser desorption followed by resonant laser post-ionization. A single-shot detection limit in the 10?6 monolayer range was found for aniline adsorbed on silica, a system whose adsorption, laser desorption and ionization properties have been well studied. An excellent signal-to-noise ratio, as well as some simple modifications that will improve the detection efficiency suggest ultimate detection limits in the 10?9 to 10?10 ML range with this scheme.
Voumard, P., Zhan, Q., & Zenobi, R. (1995). Detection of Molecular-Surface Adsorbates at the 10(-6)-Monolayer Level and Below. Chemical Physics Letters, 239(1-3), 89-94. DOI: 10.1016/0009-2614(95)00436-8