TY  - GEN
KW  - pulse shaping
pulse characterisation
dispersion scan
KW  -  d-scan
acousto-optic modulator
KW  -  AOM
mid-infrared pulses
ultrashort pulses
DNQ
vibrational ladder climbing
vibrationally mediated photodissociation
N2  - Characterisation, compression and shaping of mid-infrared (MIR) pulses are demonstrated in an acousto-optic modulator (AOM) shaper based setup. Characterisation of the pulses? spectral phase is accomplished via an AOM shaper based variant of dispersion scan (d-scan). By a combination of d-scan and an evolutionary algorithm, broadband MIR pulses centred at 3.2 µm are compressed to below 50 fs FWHM autocorrelation. The shaping and characterisation capabilities of the setup are demonstrated by imprinting and retrieving a set of spectral phases of increasing complexity on compressed broadband MIR pulses. Moreover, the effect of excitation of the C=N=N stretching vibration on the photoreaction of 2-diazo-1-naphthol-5-sulfonate dissolved in methanol is investigated. The C=N=N stretch mode is excited up to at least v=3 by ultrafast MIR pulses. Molecular dissociation in the electronic ground state is not observed. Vibrational excitation decays within 20 ps. Experiments on vibrationally mediated photodissociation show that vibrational pre-excitation increases the photoreaction?s quantum yield by at least 10% compared to excitation of the molecule by a mere ultraviolet pulse. This is explained by an increased Franck-Condon overlap of the edge of the electronic ground state?s potential energy surface with the reactive part of the potential energy surface of the electronic excited state.
A1  - Nicolai, Florian Volker
CY  - Heidelberg
TI  - Shaping and characterisation by dispersion scan of ultrafast mid-infrared pulses and the effect of the CNN stretching vibration on the photoreaction of 2-diazo-1-naphthol-5-sulfonate
AV  - public
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/34218/
ID  - heidok34218
Y1  - 2023///
ER  -