物構研談話会（16-04）

概要

Catalysis at the solid surface is associated with challenging future
chemical processes in chemical industry such as transforming CO2 to
fuels and nitrogen to ammonia using renewable resources. In catalysis at
the solid surface driven by temperature, excitation of phonons as well
as frustrated rotational and translational motions of reactant species
play an important role. Recent ultrafast soft X-ray spectroscopy
experiments using LCLS x-ray laser provided additional insights into
this aspect [1-3], in which femtosecond visible laser pulse was used
initiate reactions by producing high transient electronic temperatures
followed by energy transfer to atomic and molecular motions. It would be
highly desirable to drive chemical reactions by direct motional
excitations on ultrafast timescales.

We have recently demonstrated that the strong electric field of THz
radiation from a linear accelerator can activate a chemical bond through
electron migration near the Fermi level [4]. The study showed that the
CO and O co-adsorbed system on Ru could be steered towards oxidation
using the strong electric field of THz radiation, whereas CO desorption
dominates in thermal and optical laser stimulated reactions. In the
future, we propose to explore the possibility of steering a chemical
reaction at the solid-liquid interface. Using the strong electric field
of THz radiation, we intend to steer an electrochemical reaction through
a migration of either electrons in the solid or ions in the liquid.



References

[1] M. Dell'Angela et al., Science 339, 1302 (2013)

[2] H. Ostrom et al., Science 347, 978 (2015)

[3] M. Beye et al, J. Phys. Chem. Lett., 7, 3647 (2016)

[4] J.L. LaRue et al, Phys. Rev. Lett. 115, 036103 (2015)