Abstract
Bonding and anti-bonding modes of plasmon coupling effects are numerically investigated in TiO2-Ag core-shell nano dimers. First, splitting phenomena of the coupled anti-bonding modes are observed under the longitudinal polarization when the distance between the monomers decreases to a certain level. Second, one of the split resonance modes is identified to be formed by the dipole anti-bonding mode of the monomers from charge density distribution patterns. Those split modes have similar redshift behaviors as the coupled dipole bonding modes in the same situations. Furthermore, the intensities of those anti-bonding modes weaken with decreasing distance between the monomers, because of the interaction of the induced dipole moment in the monomers and the charge distribution variation on the facing surfaces of the gap by the coulomb attraction. Other split bands are the higher-order mode (octupole-like or triakontadipole-like), which do not have obvious peak-shift behavior, and the intensities have very little attenuation with decreasing distance. Finally, the coupling of the bonding and anti-bonding modes under the longitudinal polarization is symmetric (bonding).
Highlights
Bonding and anti-bonding modes of plasmon coupling effects are numerically investigated in TiO2-Ag core-shell nano dimers
The coupling of the local surface plasmon resonance (LSPR) in nanostructures is a fundamental plasmonic effect related to many practical applications, such as hot spots for surface enhanced spectroscopy[1,2,3], local energy deposition[4,5,6], refractive index sensors[7], and plasmon ruler for the distance sensing[8,9,10]
In the dimer configuration, when the light polarization is along the axis of the dimers, the coupled resonance peaks exhibit the redshift behavior as the distances between two monomers decrease; the intensities of the plasmonic resonance peaks increase in general[2,9,10,24,27], whereas the coupled resonance peaks show the blueshift behavior as the distances decrease[7,9,13,14,15,20] while the intensities of the peaks decrease[9] when the polarization is perpendicular to the axis of the dimers
Summary
Bonding and anti-bonding modes of plasmon coupling effects are numerically investigated in TiO2-Ag core-shell nano dimers. One of the split resonance modes is identified to be formed by the dipole anti-bonding mode of the monomers from charge density distribution patterns. Those split modes have similar redshift behaviors as the coupled dipole bonding modes in the same situations. The bonding and anti-bonding modes of the plasmon coupling effects of the TiO2-Ag core-shell dimers are investigated. The single TiO2-Ag core shell nanostructure has shown two equal intensity dipole plasmon resonance modes, in which one resonance mode is bonding and the other is anti-bonding[32]. The features of the coupled anti-bonding modes and the coupled bonding modes, the peak-shift behaviors, and their intensity dependence are discussed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
