Abstract
UV spectroscopy and electronic circular dichroism (ECD) experiments on supersonic-beam-cooled deuterated (R)-(+)-3-methylcyclopentanone ([D4]-(R)-(+)-3-MCP) have been performed by using a laser mass spectrometer. The spectral resolution not only allowed excitation and CD measurements for single vibronic transitions but also for the rotational P, Q, and R branches of these transitions. The investigated n →π(1804 2501) transition showed the largest anisotropy factor ever observed for chiral molecules in the gas phase, which, due to residual saturation of the excited transition, represents only a lower limit for the real anisotropy factor. Furthermore, one-color (1+1+1) and two-color (1+1′) resonance-enhanced multiphoton ionization (REMPI) measurements were performed and the effusive-beam (room temperature) and supersonic-beam results for [D4]-(R)-(+)-3-MCP were compared. These results allowed a differentiation between single-step ECD (comparable to conventional ECD) and cumulative ECD (only possible in multiphoton excitation) under supersonic-beam conditions.
Original language | English |
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Pages (from-to) | 4052-4058 |
Number of pages | 7 |
Journal | ChemPhysChem |
Volume | 17 |
Issue number | 24 |
DOIs | |
State | Published - 15 Dec 2016 |
Keywords
- circular dichroism
- mass spectrometry
- resonance-enhanced multiphoton ionization
- rotational spectroscopy
- supersonic beam cooling