Science Daily October 18, 2022
An international team of researchers (Germany, USA – UC Irvine) used electric-field-resolved spectroscopy and quantum-chemical modelling to precisely measure and describe the complete coherent energy transfer between octave-spanning mid-infrared waveforms and vibrating molecules in aqueous solution. The sub-optical-cycle temporal resolution of their technique revealed alternating absorption and (stimulated) emission on a few-femtosecond time scale. This behaviour can only be captured when effects beyond the rotating wave approximation are considered. At a femtosecond-to-picosecond timescale, optical-phase-dependent coherent transients, and the dephasing of the vibrations of resonantly excited methylsulfonylmethane (DMSO2) were observed. Ab initio modelling using density functional theory traces these dynamics back to molecular-scale sample properties, in particular vibrational frequencies, and transition dipoles, as well as their fluctuation due to the motion of DMSO2 through varying solvent environments. According to the researchers future extension of their study to nonlinear interrogation of higher-order susceptibilities is possible with state-of-the-art lasers…read more. Open Access TECHNICAL ARTICLEÂ
Time-integrated and time-resolved broadband vibrational spectroscopy. Credit: Nature Communications volume 13, Article number: 5897 (2022)Â