Nitro Stretch Probing of a Single Molecular Layer to Monitor Shock Compression with Picosecond Time-Resolution

Abstract. Ultrafast shock compression vibrational spectroscopy experiments with molecular monolayers provide atomic-scale time and space resolution, which enables critical testing of reactive molecular simulations. Since the origination of this project, we have greatly improved the ability to detect shocked monolayers by nonlinear coherent vibrational spectroscopy with nonresonant sup-pression. In this study, we show new results on a nitroaromatic monolayer, where the nitro symmetric stretch is probed. A small frequency blue-shift under shock conditions compared to measurements with static high pressure shows the shock is ~1 GPa. The ability to flash-preheat the monolayer by several hundred K is demonstrated. In order to observe shock monolayer chemistry in real time, along with pre-heating, the shock pressure needs to be increased and methods to do so are described. Keywords : laser-driven shock, femtosecond spectroscopy, molecular monolayers PACS : 62.50.+p, 78.47.+p, 68.35.Ja, 78.30.-j