Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How molecules teeter in a laser field

18.01.2019

When molecules interact with the oscillating field of a laser, an instantaneous, time-dependent dipole is induced. This very general effect underlies diverse physical phenomena such as optical tweezers, for which Arthur Ashkin received the Nobel Prize in Physics in 2018, as well as the spatial alignment of molecules by a laser field. Now scientists from the Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (MBI) report on an experiment in the Journal of Physical Chemistry Letters, where the dependence of the driven-dipole response on the bound state of an electron in a methyl iodine molecule is revealed.

The reported work represents the first attosecond transient absorption spectroscopy (ATAS) experiment on a polyatomic molecule. In an ATAS experiment, the absorption of photons in the extreme ultraviolet (XUV) spectral range (provided in the form of an isolated attosecond pulse or an attosecond pulse train) is studied in the presence of an intense infrared laser field, whose relative phase with respect to the XUV radiation is controlled.


Measured transient change of the XUV absorbance in the 4d-core-to-valence (σ*) and 4d-core-to-Rydberg spectral region in CH3I molecules. Pronounced sub-cycle oscillations at twice the NIR laser frequency are observed in the region of the core-to-Rydberg transitions, while the core-to-valence transitions are only weakly affected by the field. The observed effect is traced back to the higher polarizability of the Ryberg states, which makes them more susceptible to the interaction with the laser field

Credit: MBI Berlin

Usage Restrictions: The image may only be used with appropriate caption and credit.

By performing such an experiment on molecules, the MBI researchers could access a spectral regime, where transitions from the atomic cores to the valence shell can be compared with transitions from the cores to the Rydberg shell.

"Initially somewhat surprising, we found that the infrared field affects the weak core-to-Rydberg transitions much more strongly than the core-to-valence transitions, which dominate the XUV absorption," says MBI scientist Lorenz Drescher. The published paper is part of his PhD work at MBI.

Accompanying theory simulations revealed that the Rydberg states dominate the laser-dressed XUV absorption due to their high polarizability. Importantly, the reported experiment offers a glimpse into the future.

"By tuning the XUV spectrum to different absorption edges, our technique can map the molecular dynamics from the local perspective of different intra-molecular reporter atoms," explains MBI scientist Dr. Jochen Mikosch.

"With the advent of attosecond XUV light sources in the water window, ATAS of light-induced couplings in molecules is anticipated to become a tool to study ultrafast phenomena in organic molecules," he adds. In this wavelength regime, transitions from core-orbitals in nitrogen, carbon and oxygen atoms are located. MBI is at the forefront of developing such light sources, which will allow the researchers to study the building blocks of life.

Media Contact

Jochen Mikosch
jochen.mikosch@mbi-berlin.de
49-306-392-1295

http://www.fv-berlin.de 

Jochen Mikosch | EurekAlert!
Further information:
https://www.mbi-berlin.de/en/current/index.html#2019_01_17
http://dx.doi.org/10.1021/acs.jpclett.8b02878

More articles from Life Sciences:

nachricht New mechanisms regulating neural stem cells
21.02.2019 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht A landscape of mammalian development
21.02.2019 | Max-Planck-Institut für molekulare Genetik

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Light from a roll – hybrid OLED creates innovative and functional luminous surfaces

Up to now, OLEDs have been used exclusively as a novel lighting technology for use in luminaires and lamps. However, flexible organic technology can offer much more: as an active lighting surface, it can be combined with a wide variety of materials, not just to modify but to revolutionize the functionality and design of countless existing products. To exemplify this, the Fraunhofer FEP together with the company EMDE development of light GmbH will be presenting hybrid flexible OLEDs integrated into textile designs within the EU-funded project PI-SCALE for the first time at LOPEC (March 19-21, 2019 in Munich, Germany) as examples of some of the many possible applications.

The Fraunhofer FEP, a provider of research and development services in the field of organic electronics, has long been involved in the development of...

Im Focus: Regensburg physicists watch electron transfer in a single molecule

For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.

The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...

Im Focus: University of Konstanz gains new insights into the recent development of the human immune system

Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens

Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...

Im Focus: Transformation through Light

Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light

When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...

Im Focus: Famous “sandpile model” shown to move like a traveling sand dune

Researchers at IST Austria find new property of important physical model. Results published in PNAS

The so-called Abelian sandpile model has been studied by scientists for more than 30 years to better understand a physical phenomenon called self-organized...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Global Legal Hackathon at HAW Hamburg

11.02.2019 | Event News

The world of quantum chemistry meets in Heidelberg

30.01.2019 | Event News

Our digital society in 2040

16.01.2019 | Event News

 
Latest News

A Volcanic Binge And Its Frosty Hangover

21.02.2019 | Earth Sciences

Cleaning 4.0 in the meat processing industry – higher cleaning efficiency

21.02.2019 | Trade Fair News

New mechanisms regulating neural stem cells

21.02.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>