Description:

Vibrational spectroscopy at the single-molecule level opens new avenues of research, both experimental and theoretical.  By probing individual molecules, it should be possible to explore how vibrational properties are affected by neighboring coadsorbed molecules or surface defects. It is widely believed that such local effects play a critical role in surface chemistry. The combination of atomic resolution offered by STM (Scanning Tunneling Microscopy) and vibrational spectroscopy also allows the creation of atomic-scale spatial images of the inelastic tunneling channel for each vibrational mode.  Thus, individual adsorbed molecules can be identified by their vibrational spectra and inelastic images.

The above images are representative spectroscopic spatial imaging of the inelastic channels for C₂H₂ and C₂D₂. (A) Regular (constant current) STM image of a C₂H₂ molecule (left) and a C₂D₂ molecule (right). Data are the average of the STM images recorded simultaneously with the vibrational images. The imaged area is 48 Å by 48 Å. d²I/dV² images of the same area recorded at (B) 358 mV, (C) 266 mV, and (D) 311 mV are the average of four scans of 25 min each with a bias modulation of 10 mV. All images were scanned at 1 nA dc tunneling current. The symmetric, round appearance of the images is attributable to the rotation of the molecule between two equivalent orientations during the experiment.

 Previous Day/Next Day

Please contact the webmaster if you would like to submit an image