Mapping wave packet bifurcation at a conical intersection in CH3I by attosecond XUV transient absorption spectroscopy
- Univ. of California, Berkeley, CA (United States)
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Univ. Complutense de Madrid (Spain)
- Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Extreme ultraviolet (XUV) transient absorption spectroscopy has emerged as a sensitive tool for mapping the real-time structural and electronic evolution of molecules. Here, attosecond XUV transient absorption is used to track dynamics in the A-band of methyl iodide (CH3I). Gaseous CH3I molecules are excited to the A-band by a UV pump (277 nm, ~20 fs) and probed by attosecond XUV pulses targeting iodine I(4d) core-to-valence transitions. Owing to the excellent temporal resolution of the technique, passage through a conical intersection is mapped through spectral signatures of nonadiabatic wave packet bifurcation observed to occur at 15 ± 4 fs following UV photoexcitation. The observed XUV signatures and time dynamics are in agreement with previous simulations [H. Wang, M. Odelius, and D. Prendergast, J. Chem. Phys. 151, 124106 (2019)]. Furthermore, due to the short duration of the UV pump pulse, coherent vibrational motion in the CH3I ground state along the C-I stretch mode (538 ± 7 cm-1) launched by resonant impulsive stimulated Raman scattering and dynamics in multiphoton excited states of CH3I are also detected.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1840946
- Alternate ID(s):
- OSTI ID: 1788285
- Journal Information:
- Journal of Chemical Physics, Vol. 154, Issue 23; ISSN 0021-9606
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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