Time-Evolving Chirality Loss in Molecular Photodissociation Monitored by X-ray Circular Dichroism Spectroscopy.
Yeonsig NamDaeheum ChoBing GuJérémy R RouxelDaniel KeeferNiranjan GovindShaul MukamelPublished in: Journal of the American Chemical Society (2022)
The ultrafast photoinduced chirality loss of 2-iodobutane is studied theoretically by time- and frequency-resolved X-ray circular dichroism (TRXCD) spectroscopy. Following an optical excitation, the iodine atom dissociates from the chiral center, which we capture by quantum non-adiabatic molecular dynamics simulations. At variable time delays after the pump, the resonant X-ray pulse selectively probes the iodine and carbon atom involved in the chiral dissociation through a selected core-to-valence transition. The TRXCD signal at the iodine L 1 edge accurately captures the timing of C-I photodissociation and thereby chirality loss, c.a 70 fs. The strong electric dipole-electric quadrupole (ED-EQ) response makes this signal particularly sensitive to vibronic coherence at the high X-ray regime. At the carbon K-edges, the signals monitor the molecular chirality of the 2-butyl radical photoproduct and the spin state of the iodine atom. The ED-EQ response is masked under the strong electric dipole-magnetic dipole response, making this signal intuitive for the electronic population. The evolution of the core electronic states and its chiral sensitivity is discussed. Overall, the element-specific TRXCD signal provides a detailed picture of molecular dynamics and offers a unique sensitive window into the time-dependent chirality of molecules.
Keyphrases
- dual energy
- molecular dynamics
- high resolution
- computed tomography
- density functional theory
- single molecule
- molecular dynamics simulations
- electron transfer
- emergency department
- mass spectrometry
- energy transfer
- capillary electrophoresis
- ionic liquid
- magnetic resonance imaging
- molecular docking
- contrast enhanced
- small molecule
- blood pressure
- high speed
- solid state
- magnetic resonance
- tandem mass spectrometry
- electron microscopy
- molecularly imprinted
- quantum dots
- ms ms