Schedule Logo
Poster Session

Poster Session II

4:00 pm – 6:00 pm, Wednesday June 18 Session H00 Oregon Convention Center, Exhibit Hall E
Topics:
PrevNext

Methylation effect on positron annihilation and binding.

Poster 18
Presenter: Eugene Arthur-Baidoo (University of California, San Diego)
Authors: J. R. Danielson (University of California, San Diego), C. Surko (University of California, San Diego)

Positron binding and annihilation has been reported for many molecules including large alkane and aromatic compounds [1]. Recently, a good-to-excellent agreement has been obtained between measured binding energies (εb) and the theoretical predictions which take into account electron-positron correlations, including virtual-positronium formation [2]. Here, we report positron annihilation and εb for both methylated benzene and pyridine molecules. In both cases, a correlation is observed between the increases in annihilation rate and εb with increasing number of methyl groups. For nitrogen containing compounds, such as methylpyridines, it is observed that methyl groups located far from the nitrogen exhibited the highest annihilation rate, compared to those closer to it. However, different subsitution sites (m-, o-, p- or 2-, 3-, 4-) for the methylated groups in each series do not show a significant change in εb values (i.e., ∆εb/εb < 5%). Additional results, including the influence of geometry and molecular parameters will be disccussed. [1] E. Arthur-Baidoo et. al., Phys. Rev. A 109, 062801 (2024). [2] J. Hofierka et al., Nature 606, 688-693 (2022)

Funding acknowledgement

Work supported by the NSF grant PHY-2306404 and the UCSD Foundation.

POSTERS (156)