High-resolution x-ray spectra of carbon monoxide reveal ultrafast dynamics induced by long UV pulse

• In theoretical simulations of a UV + x-ray pump-probe (UVX-PP) setup, we show that frequency detuning of the pump UV pulse acts as a camera shutter by regulating the duration of the UVX-PP process. This two-photon absorption with long overlapping UV and x-ray pulses, allowing for high spectral resolution, thereby provides information about ultrafast dynamics of the nuclear wave packet without the requirement of ultrashort pulses and controlled delay times. In a case study of carbon monoxide, the calculated UVX-PP spectra of the O1s (-1)2 pi (1) and C1s (-1)2 pi (1) core-excited states show different vibrational profiles. The interference of intermediate vibrational states reveals details of nuclear dynamics in the UVX-PP process related to a variable duration time controlled by the UV detuning. Both O1s (-1)2 pi (1) and C1s (-1)2 pi (1) pump-probe channels display a splitting of the spectral profile, which however is associated with different physical mechanisms. At the O1s (-1)2 pi (1) resonance, the observed dispersive and non-dispersive spectral bands intersect and result in destructive interference.

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

NATURVETENSKAP  -- Kemi -- Teoretisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Theoretical Chemistry (hsv//eng)

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

UV pump-x-ray probe

molecular spectroscopy

ultrafast dynamics

potential energy surfaces

x-ray absorption

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