Visualizing vibrational normal modes of a single molecule with atomically confined light

Lee, Joon‐Hee; Crampton, Kevin T.; Tallarida, Nicholas; Apkarian, V. A.

doi:10.1038/s41586-019-1059-9

Cited by 448 publications

(436 citation statements)

References 32 publications

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“…1d that the spatial resolution (the full width at the half maximum) can reach 1.5(1) Å ( Fig. 1e) , at the same Ångström level as the reported resolution of ~1.67 Å by J. Lee et al 2 Such a high resolution enables vibrational imaging at the single-chemical-bond level.…”

Section: Mg-porphine Molecule Requires Only a Few Vibrational Images supporting

confidence: 74%

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Visually constructing the chemical structure of a single molecule by scanning Raman picoscopy

Zhang

Yang

Ghafoor

et al. 2019

National Science Review

114

100

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The strong spatial confinement of a plasmonic field has made it possible to visualize the inner structure of a single molecule and even distinguish the vibrational modes in real space 1-4 . With such ever-improved spatial resolution, it is anticipated that full vibrational imaging of a molecule could be achieved to reveal molecular structural details. Here, we present a new technique, named as scanning Raman microscopy, to utilize for visually constructing the chemical structure of a single molecule. It is achieved by taking advantage of three key elements. First, the full mapping of individual vibrational modes with Ångström-level resolution allows to visually determine the placements of atoms or chemical bonds. Second, the positiondependent interference effect for symmetric and anti-symmetric vibrations enables to identify the connectivity of the chemical groups involved. The third element is the combination of spectromicroscopic images and Raman fingerprints for different chemical groups that conclusively ensures the definite arrangement of constituent

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Section: Mg-porphine Molecule Requires Only a Few Vibrational Images supporting

confidence: 74%

“…When the tip is on the top of an atom α, the Raman signal from this atom becomes dominated, as represented by the first term of Eq. (2). When the tip is located at the middle of two atoms, an interference effect is expected to take place due to the cross-term * α β ϕ ϕ .…”

Section: Mg-porphine Molecule Requires Only a Few Vibrational Images mentioning

confidence: 99%

Visually constructing the chemical structure of a single molecule by scanning Raman picoscopy

Zhang

Yang

Ghafoor

et al. 2019

National Science Review

114

100

View full text Add to dashboard Cite

show abstract

“…The combination of ultrafast laser pulses with scanning tunneling microscopy (STM) promises advancements in surface science by connecting sub-nanometer resolution with light-driven dynamics [1][2][3][4][5]. Various optically induced phenomena have been investigated on an atomic level, such as surface photochemical reactions [6][7][8][9][10][11][12][13], photo-induced molecular motion [14][15][16][17][18][19], charging of individual molecules, defects, dopants and nanostructures [20][21][22][23][24][25][26], and tip-enhanced Raman scattering by nanostructures and single molecules [27][28][29][30][31][32]. Time-resolved STM operation gains particular attention in the form of pump-probe excitation of dynamical processes, which can reach the femtosecond (fs) domain [9, 16, 21-23, 25, 33-39].…”

Section: Introductionmentioning

confidence: 99%

Controlling photocurrent channels in scanning tunneling microscopy

et al. 2020

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We investigate photocurrents driven by femtosecond laser excitation of a (sub)-nanometer tunnel junction in an ultrahigh vacuum low-temperature scanning tunneling microscope (STM). The optically driven charge transfer is revealed by tip retraction curves showing a current contribution for exceptionally large tip-sample distances, evidencing a strongly reduced effective barrier height for photoexcited electrons at higher energies. Our measurements demonstrate that the magnitude of the photo-induced electron transport can be controlled by the laser power as well as the applied bias voltage. In contrast, the decay constant of the photocurrent is only weakly affected by these parameters. Stable STM operation with photoelectrons is demonstrated by acquiring constant current topographies. An effective non-equilibrium electron distribution as a consequence of multiphoton absorption is deduced by the analysis of the photocurrent using a one-dimensional potential barrier model.

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“…Raman spectroscopy is a powerful technique for revealing intrinsic local chemical information in different types of systems, and is important in physics, material science, chemistry, biology, and medicine [1][2][3][4][5][6][7][8][9][10][11]. As spontaneous Raman signal is inherently weak, different types of Raman spectroscopy have been proposed and developed, such as surface-enhanced [12][13][14][15], tip-enhanced [16,17], femtosecond-stimulated [18][19][20], femtosecond time-resolved impulsive stimulated [21], polarized [22,23], and shifted excitation [24,25] Raman spectroscopy. Recently, in surface-enhanced Raman spectroscopy (SERS), the so-called 'nanopipette' structures [26,27] and nanoparticles-coated optical fiber-tip probes have garnered significant interest [28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Investigation of optical fiber-tip probes for common and ultrafast SERS

et al. 2020

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In this study, we performed a three-dimensional computational experiment on ultrashort pulse propagation in an optical fiber-tip probe that is decorated with gold nanoparticles (NPs) using a constant structure for the probe's dielectric taper and different spatial configurations of the gold nanoparticles. Interestingly, a hot spot with the highest amplitude of the electric field was found not along the same chain of the NPs but between terminal NPs of neighboring chains of NPs at the probe's tip (the amplitude of the electric field in the hot spots between the NPs along the same chain was of the order of 10 1 , while that between terminal NPs of neighboring chains was of the order of 10 3 ). We eventually identified a configuration with only six terminal nanoparticles (Config4) which is characterized by the highest electric field amplitude enhancement and can provide the highest spatial resolution in the SERS interrogation of an object of interest. The ultrashort temporal responses of the hot spots for all configurations exhibited relatively high pulse elongation (relative elongation was greater than 4.3%). At the same time, due to the reflection of the incident pulse and consequent interference, the temporal responses of most hot spots contained several peaks for all configurations except for the optimum Config4. Nonetheless, the ultrashort temporal responses of all hot spots for Config4 were characterized by a single peak but with a relatively large pulse elongation (relative elongation was 234.1%). The results indicate that further examination of this new structure of a nanoparticles-coated optical fiber-tip probe with only six terminal NPs may provide attractive characteristics for its practical applications.

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Visualizing vibrational normal modes of a single molecule with atomically confined light

Cited by 448 publications

References 32 publications

Visually constructing the chemical structure of a single molecule by scanning Raman picoscopy

Visually constructing the chemical structure of a single molecule by scanning Raman picoscopy

Controlling photocurrent channels in scanning tunneling microscopy

Investigation of optical fiber-tip probes for common and ultrafast SERS

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