Understanding and Controlling the Astounding Molecule That Made the Universe

That’s when chemists using femtosecond lasers come into play. Rather than study the stars using a telescope, Dantus’ team literally looks at the small picture. The entire procedure is viewed at the molecular level and is measured in femtoseconds – 1 millionth of 1 billionth of a second. The process the team views takes between 100 and 240 femtoseconds. Dantus knows this because the clock starts when he fires the first laser pulse. The laser pulse then “sees” what’s happening.

The two-laser technique revealed the hydrogen transfer, as well as the hydrogen-roaming chemistry, that’s responsible for H3+ formation. Roaming mechanisms briefly generate a neutral molecule (H2) that stays in the vicinity and extracts a third hydrogen molecule to form H3+. And it turns out there’s more than one way it can happen. In one experiment involving ethanol, the team revealed six potential pathways, confirming four of them.

Since laser pulses are comparable to sound waves, Dantus’ team discovered a “tune” that enhances H3+ formation and one that discourages formation. When converting these “shaped” pulses to a slide whistle, successful formation happens when the note starts flats, rises slightly and finishes with a downward, deeper dive. The song is music to the ears of chemists who can envision many potential applications for this breakthrough.

“These chemical reactions are the building blocks of life in the universe,” Dantus said. “The prevalence of roaming hydrogen molecules in high-energy chemical reactions involving organic molecules and organic ions is relevant not only for materials irradiated with lasers, but also materials and tissues irradiated with x-rays, high energy electrons, positrons and more.”

This study reveals chemistry that is relevant in terms of the universe’s formation of water and organic molecules. The secrets it could unlock, from astrochemical to medical, are endless, he added.

This research was funded by the Department of Energy and the National Science Foundation.

Contacts and sources:
Layne Cameron
Michigan State University

Citation:

H2 roaming chemistry and the formation of H3+ from organic molecules in strong laser fields
Nagitha Ekanayake, Travis Severt, Muath Nairat, Nicholas P. Weingartz, Benjamin M. Farris, Balram Kaderiya, Peyman Feizollah, Bethany Jochim, Farzaneh Ziaee, Kurtis Borne, Kanaka Raju P., Kevin D. Carnes, Daniel Rolles, Artem Rudenko, Benjamin G. Levine, James E. Jackson, Itzik Ben-Itzhak & Marcos Dantus
Nature Communicationsvolume 9, Article number: 5186 (2018) https://www.nature.com/articles/s41467-018-07577-0;