2009年12月09日

Electronic movies

Strong laser fields can tear an electron away from a molecule, leaving a fole in the electronic wavefunction that races through the molecule.

The ultrafast motion ofsuch a hole has been traced at last.



The first event in a light-induced reaction is that the electrons in the irradiated molecule respond to the incident light.

This response occurs on attosecond tinescales ( 1 attosecond is 10^-18 seconds), and even the fastest time-resolved measurements have been unable to probe the dynamics of the prosess.

But on page 972 of this isse, Smirnova et al. provide a glimpse into the fascinating world of attosecond electron dynamics, in effect revealing the opening frames of a movie that records the rearrangement of electrons when a molecuke is ionized by a laser.


(… to be continue…)

### database ###
nature 460,925-1050 20 August 2009 Issue no.7258
Article p.972 / High harmonic interferometry of multi-electron dynamics in molecules / O Smirnova et al. (カナダ国家研究会議およびマックス・ボルン研究所)
news and views p.960 / Chemical Physics : Electronic movies / Marc Vrakking
物理:アト秒の世界を見る



The authors make use of the fact that molecules exposed to intense laser fields emit soft (low-energy ) X-rays, in a process that is generally referred to as shgh-harmonic generation.

In this process, an electron is extracted from a molecule by the laser, leaving behind a molecular ion.

The electron is then accelerated in the laser's oscillatry electric field, before recombining with the molrcular ion.

The recombination results in the emission of an X-ray photon.

Large numbers of (typically near-infraed ) photons are thus converted into soft-X-rey photons, which have frequencies that are multiples (harmonics) of the source laser's frequency.


(… to be continue…)
posted by 0≠素子 at 23:31| Comment(0) | chamical physics | このブログの読者になる | 更新情報をチェックする
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