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CATEGORY:
Special Seminar - Solid State Institute, Technion
TITLE:
Probing molecular-ion beams with intense few-cycle laser pulses – two-color controlled dissociation
Speaker:
Professor Itzik Ben-Itzhak
Affiliation:
Department of Physics,J.R. Macdonald Laboratory, Kansas State University, U.S.A.
WHEN:
Thursday
26/01/2017, 12:30 - 13:30
WHERE:
Lidow, Asher Peres (502)
Organizer:
-
Site:
-
Presentation:
Event Lecture notes
Remarks:
Host: Associate Professor Oren Cohen

Abstract

We have studied laser-induced fragmentation of molecular-ion beams using coincidence 3D
momentum imaging, with direct separation of all the reaction products measured simultaneously.
These measurements provide detailed kinetic energy release and angular distributions of the
different fragmentation processes. We mainly focus on the fundamental H
2+ and H3+ molecules
(in 5-50 fs laser pulses having 10
12-1016 W/cm2 peak intensity) as models for more complex
systems, and at times we explore more complex molecules such as O
2+, CO2+ and CO2+.
In this talk, I will describe controlling the nuclear degrees of freedom during dissociation of
molecular-ion beams in a strong-field, which leads to asymmetry in the direction the ionic
fragment is emitted. Specifically, the “control knob” is the relative phase between the 790 and
395 nm components of an ultrashort laser pulse. Of particular interest are phase differences (also
referred to as time delays) between the different dissociating vibrational states.
In addition, clear experimental and theoretical evidence for the intriguing zero-photon
dissociation (ZPD) process of H
2+ will be presented. The key role of the laser-pulse bandwidth
and chirp on ZPD control will be discussed. Moreover, we will explore control over the final
dissociation product of HD
+, either H+ + D or H + D+ – namely controlling their branching ratio.

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