LONDON – Ultrafast pulses of laser light fired at oxygen, nitrogen and carbon monoxide molecules could pave the way toward imaging the movement of atoms and their electrons as they undergo chemical reactions – one of the holy grails of chemistry research.
A team from Max Born Institute in Berlin, FOM-Institute AMOLF in Amsterdam and Texas A&M University in College Station fired pulses that span only a few hundred attoseconds at a sample of molecules to map the quick movements of atoms within the molecules as well as the charges that surround them.
Previous research probed at the structure of molecules using a variety of techniques; however, the inherent challenge is to perform these experiments in systems where changes are rapidly occurring on very small timescales.
In the new work, short laser pulses were fired at the target molecule in an attempt to dislodge an electron. This photoionization process images atoms and molecules in unprecedented detail.
Photoelectron angular distributions for the ionization of aligned and anti-aligned molecules using an attosecond pulse train. CO2 = carbon dioxide. Courtesy of Arnaud Rouzée, Max Born Institute.
The researchers wanted to monitor in real time the electrical and molecular changes that occurred as an atom underwent a chemical reaction. They intended to do this by triggering a reaction with the laser, breaking the chemical bond that held the molecules together and using the photoionization method to image the changes that occurred in the molecule as they happened.
“We show that the photoelectron spectra recorded for a small molecule, such as oxygen, nitrogen and carbon monoxide, contain a wealth of information about electron orbitals and the underlying molecular structure,” said Dr. Arnaud Rouzée of Max Born Institute, lead author of the study. “This is a proof-of-principle experiment that electrons ejected within the molecule can be used to monitor ultrafast electronic and atomic motion.”
The study was published in IOP Publishing’s Journal of Physics B: Atomic, Molecular and Optical Physics