Selective Raman Enhancement with Electronic Sensitivity in Tip-Enhanced Raman Spectroscopy

Abstract

Chemical interaction between the tips and molecules is one of the main contributing mechanisms to tip-enhanced Raman spectroscopy (TERS). In this work, we calculate the TERS spectra of the biphenylene (BP) dimer at 13 nonequivalent tip sites by means of density functional theory and explore the influence of the TERS tip on vibrational mode characters and Raman intensity. The Raman intensity of the vibrational mode involving the antisymmetric stretching of tetra-rings is found to be specifically enhanced. We attribute this specific enhancement to the electronic sensitive atom vibrational character of the mode and infer that the vibrational strength of atoms can be tuned by the TERS tip. The results provide an intuitive interpretation on the effects of tip-induced electronic redistributions on specific vibrational modes in TERS and indicate the possibility to further improve the TERS resolution.

Localized vibrational characteristics of biphenylene strips resulting in length-dependent Raman spectra

“…In addition, to identify vibrational modes of Raman bands, the contribution of each atom to the normal mode in redundant internal coordinates is converted into Cartesian coordinates by adding the relative weight of their displacements and is defined as atom-vibrational strength in this work. 31 The sum of the vibrational strengths of all atoms in a vibrational mode is normalized to 1.…”

Activity Origin and Catalytic Mechanism of the M–N–C Catalysts for the Oxygen Reduction Reaction

“…Combining SERS and scanning tunneling microscopy (STM) to reveal the origin of ORR activity is essential to address this issue. Ultrahigh vacuum tip enhanced Raman spectroscopy (UHVTERS) is a valuable method to combine the chemical information on SERS with the ultrahigh spatial resolution of STM. − UHVTERS can provide not only chemical information at subnanometer spatial resolution but adsorption-geometry information under controlled environments. , …”