Selective excitation of atomic-scale dynamics by coherent exciton motion in the non-born–Oppenheimer regime

Author
Nie, Zhaogang.
Long, Run.
Li, Jialin.
Zheng, Yi Ying.
Prezhdo, Oleg V.
Loh, Zhi-Heng.
Date of Issue
2013School
School of Physical and Mathematical Sciences
Version
Accepted version
Abstract
Time-domain investigations of the nonadiabatic coupling between
electronic and vibrational degrees of freedom have focused primarily on the formation
of electronic superpositions induced by atomic motion. The effect of electronic
nonstationary-state dynamics on atomic motion remains unexplored. Here, phasecoherent
excitation of the two lowest electronic transitions in semiconducting singlewalled
carbon nanotubes by broadband <5-fs pulses directly triggers coherent exciton
motion along the axis of the nanotubes. Optical pump−probe spectroscopy with sub-10-fs
time resolution reveals that exciton motion selectively excites the high-frequency G mode
coherent phonon, in good agreement with results obtained from time-domain ab initio
simulations. This observed phenomenon arises from the direct modulation of the C−C
interatomic potential by coherent exciton motion on a time scale that is commensurate
with atomic motion. Our results suggest the possibility of employing light-field
manipulation of electron densities in the non-Born−Oppenheimer regime to initiate
selective atomic motion.
Subject
DRNTU::Science::Chemistry::Physical chemistry
Type
Journal Article
Series/Journal Title
The journal of physical chemistry letters
Rights
© 2013 American Chemical Society. This is the author created version of a work that has been peer reviewed and accepted for publication by The Journal of Physical Chemistry Letters, American Chemical Society. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1021/jz401945m].
Collections
http://dx.doi.org/10.1021/jz401945m
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