Speaker
Description
One way to probe the molecular interactions of a material is by using terahertz (THz) spectroscopy, which has been used to study L-alanine in detail [1]. However, isotropic THz spectroscopy has limitations in identifying the origin of vibrational modes since the direction of the associated dipole moment is random in an isotropic THz measurement. Therefore, there is a benefit to performing anisotropic (polarised) THz measurements. This work represents the first anisotropic measurements performed on L-alanine, the simplest chiral amino acid, and one of the earliest amino acids fundamental to early life on Earth [2].
An appropriate sample for anisotropic measurements must be highly single-crystalline. This presentation describes a method to prepare and test a sample for anisotropic THz measurements. Samples have been grown at the University of Wollongong, and sample verification has been done at ACNS’s Taipan triple-axis spectrometer. Using Taipan, a narrow mosaic spread of ~0.8° was determined, and single, well-fitted Gaussian peaks were observed in both sample rotation and Q-space scans, suggesting high single-crystallinity in our L-alanine samples. Additionally, the Taipan measurements were able to verify the orientation of the L-alanine single crystals with respect to their crystallographic axes.
Anisotropic THz measurements were taken on the THz – Far Infrared beamline at the Australian Synchrotron using a wire-grid polariser. Distinct absorption bands were observed for different crystal orientations, further confirming single-crystallinity, and identifying the dipole moment directions for the observed modes. We thus demonstrate a method of performing anisotropic THz measurements.
[1] T. J. Sanders et al., J. Chem. Phys., 154, 244311 (2021)
[2] V. Kubyshkin and N. Budisa, Int. J. Mol. Sci., 20, 5507 (2019)
| Students Only - Are you interested in AINSE student funding | Yes |
|---|---|
| Level of Expertise | Student |
| Which facility did you use for your research | Australian Synchrotron |
| Do you wish to take part in the Student Poster Slam | No |
| Presenter Gender | Man |
| Pronouns | He/Him |
| Condition of submission | Yes |
