Development of Interface-Specific Two-Dimensional Vibrational-Electronic (i2D-VE) Spectroscopy for Vibronic Couplings at Interfaces

Authors

Yuqin Qian, Utah State UniversityFollow
Zhi-Chao Huang-Fu, Utah State UniversityFollow
Jesse B. Brown, Utah State UniversityFollow
Yi Rao, Utah State UniversityFollow

Document Type

Article

Author ORCID Identifier

Yi Rao https://orcid.org/0000-0001-9882-1314

Journal/Book Title

Spectroscopy Journal

Publication Date

1-3-2025

Publisher

MDPI AG

Journal Article Version

Version of Record

Volume

3

Issue

1

First Page

1

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.

Last Page

12

Abstract

Bulk 2D electronic–vibrational (2D-EV) and 2D vibrational–electronic spectroscopies (2D-VE) were previously developed to correlate the electronic and vibrational degrees of freedom simultaneously, which allow for the study of couplings between electronic and vibrational transitions in photo-chemical systems. Such bulk-dominated methods have been used to extensively study molecular systems, providing unique information such as coherence sensitivity, molecular configurations, enhanced resolution, and correlated states and their dynamics. However, the analogy of interfacial 2D spectroscopy has fallen behind. Our recent work presented interface-specific 2D-EV spectroscopy (i2D-EV). In this work, we develop interface-specific two-dimensional vibrational–electronic spectroscopy (i2D-VE). The fourth-order spectroscopy is based on a Mach–Zehnder IR interferometer that accurately controls the time delay of an IR pump pulse pair for vibrational transitions, followed by broadband interface second-harmonic generation to probe electronic transitions. We demonstrate step-by-step how a fourth-order i2D-VE spectrum of AP3 molecules at the air/water interface was collected and analyzed. The line shape and signatures of i2D-VE peaks reveal solvent correlations and the spectral nature of vibronic couplings. Together, i2D-VE and i2D-EV spectroscopy provide coupling of different behaviors of the vibrational ground state or excited states with electronic states of molecules at interfaces and surfaces. The methodology presented here could also probe dynamic couplings of electronic and vibrational motions at interfaces and surfaces, extending the usefulness of the rich data that are obtained.

Recommended Citation

Qian, Y.; Huang-Fu, Z.-C.; Brown, J.B.; Rao, Y. Development of Interface-Specific Two-Dimensional Vibrational–Electronic (i2D-VE) Spectroscopy for Vibronic Couplings at Interfaces. Spectrosc. J. 2025, 3, 1. https://doi.org/10.3390/spectroscj3010001