Ionization Charge Dynamics Tracked | Chemical & Engineering News
Volume 93 Issue 42 | p. 23 | Concentrates
Issue Date: October 26, 2015

Ionization Charge Dynamics Tracked

Physical Chemistry: Scientists follow and control charge migration after ionizing iodoacetylene
Department: Science & Technology
[+]Enlarge
Electron-hole density in iodoacetylene is shown migrating after laser-induced ionization with the molecule oriented perpendicular to the laser polarization field.
Credit: Science
Diagram of electron hole density migration in iodoacetylene after laser-induced ionization.
 
Electron-hole density in iodoacetylene is shown migrating after laser-induced ionization with the molecule oriented perpendicular to the laser polarization field.
Credit: Science

In a step toward steering electrons inside molecules to control chemical reactivity, researchers report following electron-hole migration in iodoacetylene (H–C≡C–I) with 100-attosecond resolution after ionizing the molecule with a laser (Science 2015, DOI: 10.1126/science.aab2160). How the electron hole migrates depends on the orientation of the molecule relative to the direction the laser light is polarized. Led by ETH Zurich’s Hans Jakob Wörner, the researchers used a technique called high harmonic generation in which a laser pulse causes an electron to tunnel out and away from an atom—in this case, primarily the iodine of iodoacetylene. When the electron and hole recombine, the process releases a burst of attosecond-duration X-rays. If the molecule is perpendicular to the laser polarization field when it is ionized, the hole initially localizes on the iodine. The hole then delocalizes over the molecule before localizing on the carbons. If the molecule is parallel to the laser polarization field, the hole localizes mostly on the carbons.

 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society

Leave A Comment

*Required to comment