In quantum systems, coherent superpositions of electronic states evolve on ultrafast time scales (few femtoseconds to attoseconds; 1 attosecond = 0.001 femtoseconds = 10-18 seconds), leading to a time-dependent charge density. Here we performed time-resolved measurements using attosecond soft x-ray pulses produced by a free-electron laser, to track the evolution of a coherent core-hole excitation in nitric oxide. Using an additional circularly polarized infrared laser pulse, we created a clock to time-resolve the electron dynamics and demonstrated control of the coherent electron motion by tuning the photon energy of the x-ray pulse. Core-excited states offer a fundamental test bed for studying coherent electron dynamics in highly excited and strongly correlated matter.
|Number of pages||6|
|State||Published - 21 Jan 2022|
Bibliographical noteFunding Information:
S.L., Z. Z., and A.M. acknowledge support from US Department of Energy (DOE), BES Scientific User Facilities Division Field Work Proposal 100317; J.D. and A. M. were supported by the Laboratory Directed Research and Development Program in support of the Panofsky fellowship. The contributions from T.D., P.H.B., A.K., A.N., J.T.O., T.J.A.W., A.L.W., and J.P.C. were supported by the US DOE, Office of Science, Office of Basic Energy Sciences (BES), Chemical Sciences, Geosciences, and Biosciences Division (CSGB); E.G.C. was supported by the DOE Laboratory Directed Research and Development program at SLAC National Accelerator Laboratory, under contract DE-AC02-76SF00515. P.R. and M.F.K. acknowledge support by the German Research Foundation via KL-1439/10, and the Fellow program of the Max Planck Society. V.A, J.C.T.B., D.G., and J.P.Mar. gratefully acknowledge funding support from UK EPSRC grants EP/R019509/1, EP/T006943/1, and EP/I032517/1. N.B., R.O., and A.C.L. acknowledge the Chemical Sciences, Geosciences and Biosciences Division, US DOE, Office of Science, BES, grant DE-SC0012376. C.B. acknowledges the Swiss National Science Foundation and the National Center of Competence in Research-Molecular Ultrafast Science and Technology NCCR-MUST. L.F.D. and L.F. acknowledge support from NSF grant 1605042 and DOE DE-FG02-04ER15614. W.H. thanks the German BMBF for funding of the project “SpeAR_XFEL” under contract 05K19PE1. Use of the Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, is supported by the US DOE, Office of Science, BES, under Contract DE-AC02-76SF00515.
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