TY - JOUR
T1 - Imaging multiphoton ionization dynamics of CH3I at a high repetition rate XUV free-electron laser
AU - Cheng, Yu Chen
AU - Oostenrijk, Bart
AU - Lahl, Jan
AU - MacLot, Sylvain
AU - Augustin, Sven
AU - Schmid, Georg
AU - Schnorr, Kirsten
AU - Meister, Severin
AU - Rompotis, Dimitrios
AU - Manschwetus, Bastian
AU - Redlin, Harald
AU - Bomme, Cédric
AU - Erk, Benjamin
AU - Rolles, Daniel
AU - Boll, Rebecca
AU - Olshin, Pavel
AU - Rudenko, Artem
AU - Meyer, Michael
AU - Johnsson, Per
AU - Moshammer, Robert
AU - Gisselbrecht, Mathieu
PY - 2020
Y1 - 2020
N2 - XUV multiphoton ionization of molecules is commonly used in free-electron laser experiments to study charge transfer dynamics. However, molecular dissociation and electron dynamics, such as multiple photon absorption, Auger decay, and charge transfer, often happen on competing time scales, and the contributions of individual processes can be difficult to unravel. We experimentally investigate the Coulomb explosion dynamics of methyl iodide upon core-hole ionization of the shallow inner-shell of iodine (4d) and classically simulate the fragmentation by phenomenologically introducing ionization dynamics and charge transfer. Under our experimental conditions with medium fluence and relatively long XUV pulses (∼75 fs), we find that fast Auger decay prior to charge transfer significantly contributes to the charging mechanism, leading to a yield enhancement of higher carbon charge states upon molecular dissociation. Furthermore, we argue for the existence of another charging mechanism for the weak fragmentation channels leading to triply charged carbon atoms. This study shows that classical simulations can be a useful tool to guide the quantum mechanical description of the femtosecond dynamics upon multiphoton absorption in molecular systems.
AB - XUV multiphoton ionization of molecules is commonly used in free-electron laser experiments to study charge transfer dynamics. However, molecular dissociation and electron dynamics, such as multiple photon absorption, Auger decay, and charge transfer, often happen on competing time scales, and the contributions of individual processes can be difficult to unravel. We experimentally investigate the Coulomb explosion dynamics of methyl iodide upon core-hole ionization of the shallow inner-shell of iodine (4d) and classically simulate the fragmentation by phenomenologically introducing ionization dynamics and charge transfer. Under our experimental conditions with medium fluence and relatively long XUV pulses (∼75 fs), we find that fast Auger decay prior to charge transfer significantly contributes to the charging mechanism, leading to a yield enhancement of higher carbon charge states upon molecular dissociation. Furthermore, we argue for the existence of another charging mechanism for the weak fragmentation channels leading to triply charged carbon atoms. This study shows that classical simulations can be a useful tool to guide the quantum mechanical description of the femtosecond dynamics upon multiphoton absorption in molecular systems.
KW - Auger decay
KW - charge transfer
KW - methyl iodide dissociation
KW - recoil-ion momentum spectroscopy
KW - sequential ionization
U2 - 10.1088/1361-6455/abc6bc
DO - 10.1088/1361-6455/abc6bc
M3 - Article
AN - SCOPUS:85098881073
SN - 0953-4075
VL - 54
JO - Journal of Physics B: Atomic, Molecular and Optical Physics
JF - Journal of Physics B: Atomic, Molecular and Optical Physics
IS - 1
M1 - 014001
ER -