International Collaboration in Chemistry: Control of Ultrafast EUV-induced Chemical Reactions

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We will investigate the control of the formation and fragmentation of molecular ions by ultrashort time delayed EUV/IR light fields. The use of ultrafast laser pulses to follow in real time, and ultimately control, the reaction pathways whereby a molecule rearranges after excitation is a common and heavily studied theme in chemistry and physics today. A recent development has been the production of energetic photons in the 10-100 eV range, through high harmonic generation, with sufficient fluxes that they can be used as a beam to excite/ionize workable fractions of a macroscopic sample gas. Such photons are energetic enough to both excite and ionize the molecule. A doubly charged molecular ion typically breaks into charged fragments, and comprehensive momentum imaging technologies (known variously as COLTRIMS, reaction microscope, TRCIS, etc. 1) are available for measuring the full momentum vectors of all charged reaction products, including both ions and electrons. Following the impulsive production of an excited ionic molecule by an ultrashort EUV pulse, the fragmentation pathway can be steered using a second strong infrared pulse whose intensity, waveform and timing are control parameters. We propose to study such processes by combining the momentum-imaging expertise of one institution (KSU) with the high harmonic-generation expertise of another (MPQ).