Isomerization of One Molecule Observed through Tip-Enhanced Raman Spectroscopy.
While exploring photoisomerization of azobenzyl thiols (ABT) adsorbed on Au(111), through joint scanning tunneling microscopy (STM) and tip-enhanced Raman scattering (TERS) studies, the reversible photoisomerization of one molecule is captured in TERS trajectories. The unique signature of single molecule isomerization is observed in the form of anticorrelated flip-flops between two distinct spectra with two discrete, on- and off-levels. The apparently heterogeneously photocatalyzed reaction is assigned to cis-trans isomerization of an outlier, which is chemisorbed on the silver tip of the STM. Otherwise, the ensemble of ABT molecules that lie flat on Au(111) remain strongly coupled to the surface, excluding the possibility of photoisomerization or detection through TERS.
Department of Chemistry, University of California, Irvine , Irvine, California 92617-2025, United States.
Nicholas
N
Tallarida
Department of Chemistry, University of California, Irvine , Irvine, California 92617-2025, United States.
Laura
L
Rios
Department of Chemistry, University of California, Irvine , Irvine, California 92617-2025, United States.
Vartkess A
VA
Apkarian
Department of Chemistry, University of California, Irvine , Irvine, California 92617-2025, United States.
Joonhee
J
Lee
Au(111); Single molecule; azobenzene thiol; hetereogenous catalysis; isomerization; scanning tunneling microscopy; tip-enhanced Raman spectroscopy