67 research outputs found
Time-resolved X-ray scattering by electronic wave packets: analytic solutions to the hydrogen atom
This paper demonstrates how the time-dependent scattering signal of electronic wave packets in the hydrogen atom can be expressed analytically.</p
Selective bond breakage within the HOD molecule using optimized femtosecond ultraviolet laser pulses
Effect of <i>tert</i>-Butyl Functionalization on the Photoexcited Decay of a Fe(II)-<i>N</i>-Heterocyclic Carbene Complex
Understanding and
subsequently being able to manipulate the excited-state
decay pathways of functional transition-metal complexes is of utmost
importance in order to solve grand challenges in solar energy conversion
and data storage. Herein, we perform quantum chemical calculations
and spin-vibronic quantum dynamics simulations on the Fe-<i>N</i>-heterocyclic carbene complex, [FeÂ(btbip)<sub>2</sub>]<sup>2+</sup> (btbip = 2,6-bisÂ(3-<i>tert</i>-butyl-imidazole-1-ylidene)Âpyridine).
The results demonstrate that a relatively minor structural change
compared to its parent complex, [FeÂ(bmip)<sub>2</sub>]<sup>2+</sup> (bmip = 2,6-bisÂ(3-methyl-imidazole-1-ylidene)Âpyridine), completely
alters the excited-state relaxation. Ultrafast deactivation of the
initially excited metal-to-ligand charge transfer (<sup>1,3</sup>MLCT)
states occurs within 350 fs. In contrast to the widely adopted mechanism
of FeÂ(II) photophysics, these states decay into close-lying singlet
metal-centered (<sup>1</sup>MC) states. This occurs because the <i>tert</i>-butyl functionalization stabilizes the <sup>1</sup>MC states, enabling the <sup>1,3</sup>MLCT → <sup>1</sup>MC
population transfer to occur close to the Franck–Condon geometry,
making the conversion very efficient. Subsequently, a spin cascade
occurs within the MC manifold, leading to the population of triplet
and quintet MC states. These results will inspire highly involved
ultrafast experiments performed at X-ray free electron lasers and
shall pave the way for the design of novel high-efficiency transition-metal-based
functional molecules
Perspective: Preservation of coherence in photophysical processes
Coherence is one of the most important phenomena in ultrafast sciences. We give our perspective on the terminology, observation, and preservation of coherence in photophysical processes with some glimpses to the past and some looking-head to what may pave the way for scaling one of the last bastions in ultrafast science, namely, that of mode specific chemistry where it will be possible to break any specific bond by tailoring the pulse, an accomplishment that obviously would be the dream of any chemist
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