Abstract
The enhancement mechanism due to the molecule–surface chemical interaction in surface-enhanced Raman scattering (SERS) has been characterized using a theoretical approach based on time dependent density functional theory. This includes a systematic study of the chemical mechanism (CM) to the SERS enhancement for halogen substituted benzenethiols interacting with a silver cluster. Changing the halogen on benzenethiol enables us to systematically modulate interactions between the benzenethiol ring and the metal cluster. We observe a decrease in the CM enhancement factor with an increase in the atomic number of the halogen for para-substitutions. For meta-substitutions, there is no such trend. However, the results scale linearly with the Hammett parameters for both meta and para halogens, which provides an important predictive tool for interpreting chemical enhancements. We also study the effect of solvation on the CM, showing that there is a systematic increase in enhancement with the increasing solvent dielectric constant. The correlation of CM with other properties, such as the amount of charge transfer between adsorbate and metal and the excitation energies of charge transfer states, is much less predictive than the Hammett parameter correlation.
Original language | English (US) |
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Article number | 124706 |
Journal | Journal of Chemical Physics |
Volume | 153 |
Issue number | 12 |
DOIs | |
State | Published - Sep 28 2020 |
Funding
This work was dedicated to all inspiring role models, mentors, and collaborators (such as Professor Teri W. Odom, Professor Anna I. Krylov, Professor Svetlana Kilina, and Professor Sil-vana Andreescu). Their groundbreaking scientific contributions and mentoring have inspired many students, including the authors. Their research creativity has contributed to many different phases of physical chemistry and has impacted the scientific community at large. This research was sponsored by the Department of Energy, Office of Basic Energy Sciences, Grant No. DE-SC0004752.
ASJC Scopus subject areas
- General Physics and Astronomy
- Physical and Theoretical Chemistry