# Assessment of optimal control mechanism complexity by experimental landscape Hessian analysis: fragmentation of CH2BrI

## Author(s): Xing, Xi; Rey-de-Castro, Roberto; Rabitz, Herschel

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 Abstract: Optimally shaped femtosecond laser pulses can often be effectively identified in adaptive feedback quantum control experiments, but elucidating the underlying control mechanism can be a difficult task requiring significant additional analysis. We introduce landscape Hessian analysis (LHA) as a practical experimental tool to aid in elucidating control mechanism insights. This technique is applied to the dissociative ionization of CH2BrI using shaped fs laser pulses for optimization of the absolute yields of ionic fragments as well as their ratios for the competing processes of breaking the C-Br and C-I bonds. The experimental results suggest that these nominally complex problems can be reduced to a low-dimensional control space with insights into the control mechanisms. While the optimal yield for some fragments is dominated by a non-resonant intensity-driven process, the optimal generation of other fragments maa difficult task requiring significant additionaly be explained by a non-resonant process coupled to few level resonant dynamics. Theoretical analysis and modeling is consistent with the experimental observations. Publication Date: 2-Dec-2014 Citation: Xing, Xi, Rey-de-Castro, Roberto, Rabitz, Herschel. (2014). Assessment of optimal control mechanism complexity by experimental landscape Hessian analysis: fragmentation of CH2BrI. NEW JOURNAL OF PHYSICS, 16 (10.1088/1367-2630/16/12/125004 DOI: doi:10.1088/1367-2630/16/12/125004 ISSN: 1367-2630 Pages: 125004-1 -125004-32 Type of Material: Journal Article Journal/Proceeding Title: NEW JOURNAL OF PHYSICS Version: Final published version. This is an open access article.