Synopsis: Imaging molecular breakup

A new tool is developed to study dynamics of molecular dissociation under electron bombardment.
Synopsis figure
Illustration: H. Adaniya et al., Phys. Rev. Lett. (2009)

When low-energy electrons approach molecules, they can attach to them, forming negative ions, rather than scatter. For many molecules this process results in dissociation, leaving neutral and ionic fragments behind. This process plays a key role in radiation damage and can, for instance, cause double-strand breaks in DNA. It is not surprising, therefore, that the electron dynamics in this process called Dissociative Electron Attachment (DEA) is under much investigation, in particular for water, which is ubiquitous in living tissue. However, a clear picture of DEA is lacking for the deceptively simple water molecule due to the complex nuclear and electronic dynamics involving several transient states.

In a recent paper published in Physical Review Letters, Hidehito Adaniya and collaborators from Lawrence Berkeley National Laboratory and the University of California, Davis, both in the US, and Goethe University, Germany, have developed a new approach to probe DEA in water. By combining the calculation of the electron attachment probability in the molecular frame, obtained using ab initio methods, with momentum imaging measurements of the angular distribution of the ionic fragments in the laboratory frame, Adaniya et al. create a powerful reaction microscope. The technique is shown to work even when the standard axial recoil approximation, requiring that the recoil axis not rotate during dissociation, breaks down. This new approach opens the window for studying the dissociation of more complex molecules. – Deniz van Heijnsbergen


More Announcements »

Subject Areas

Atomic and Molecular PhysicsChemical Physics

Previous Synopsis

Next Synopsis

Related Articles

Viewpoint: The Calisthenics of Surface Femtochemistry
Chemical Physics

Viewpoint: The Calisthenics of Surface Femtochemistry

Application of a femtosecond spectroscopy technique to a copper surface has allowed the desorption of carbon monoxide molecules to be tracked with unprecedented detail. Read More »

Viewpoint: Deciphering Water’s Dielectric Constant
Chemical Physics

Viewpoint: Deciphering Water’s Dielectric Constant

The combination of two spectroscopic techniques reveals the microscopic mechanisms that control the behavior of water’s dielectric constant. Read More »

Synopsis: Hydrogen  Bonding Comes to the Rescue
Chemical Physics

Synopsis: Hydrogen Bonding Comes to the Rescue

Hydrogen bonding may safeguard biomolecules against the damaging effects of UV light. Read More »

More Articles