Abstract
Ortho-terphenyl (OTP) has long been used as a model system to study the glass transition due to its apparent simplicity and a widespread assumption that it is a rigid molecule. Here, we employ terahertz time-domain spectroscopy and low-frequency Raman spectroscopy to investigate the rigidity of OTP by direct observation of the low-frequency vibrational dynamics. These terahertz phonons involve complex large-amplitude atomic motions where intramolecular and intermolecular displacements are often mixed. Comparison of experimental results with density functional theory and ab initio molecular dynamics simulations shows that the assumption of rigidity neglects important implications for the glass transition and must be revisited. These results highlight the significance of terahertz modes on elasticity, which will be even more critical in more complex systems such as biomolecules.
| Original language | English |
|---|---|
| Pages (from-to) | 7020-7027 |
| Number of pages | 8 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 15 |
| Issue number | 27 |
| DOIs | |
| Publication status | Published Online - 1 Jul 2024 |
Funding
MTR thanks the National Science Foundation (Award Nos. CHE-2055402 and DMR-2046483), and the American Chemical Society Petroleum Research Fund (61794-DNI10) for support. JK thanks the EPSRC Cambridge Centre for Doctoral Training in Sensor Technologies and Applications (EP/L015889/1) and AstraZeneca for funding. JK and DMM acknowledge the support of the National Science Foundation (CHE-2055417) and the Hibbitt Postdoctoral Fellows Program. Publisher Copyright: © 2024 The Authors. Published by American Chemical Society
All Science Journal Classification (ASJC) codes
- General Materials Science
- Physical and Theoretical Chemistry