Comprehensive study on positron-induced molecular processes for DNA and RNA nucleobases.

The present study aims to investigate various positron-induced interaction processes for DNA and RNA nucleobases adenine, cytosine, guanine, thymine, and uracil over a broad energy range of 1-5000 eV. These processes are quantified through various cross-sections, viz., elastic (Qel), positronium formation (QPs), discrete excitation , ionization (Qion), inelastic (Qinel), and total (QT) cross-sections. We have employed the modified spherical complex optical potential (SCOP) framework with the recently developed dynamic form of the threshold parameter. The ionization processes are investigated using the complex scattering potential-ionization contribution (CSP-ic) method. To provide additional comparison, we computed Qion with the help of the binary-encounter-bethe (BEB) method as well. This work is the maiden attempt to report QT and QPs for the studied molecules except thymine and uracil. Furthermore, the present study is the first attempt to report , Qion, and Qinel for all five nucleobases. These results may provide essential input for positron transport modelling and may contribute to simulations relevant to positron emission tomography, radiation chemistry, and radiation-induced biomolecular damage.