Revealing the nature of localized and delocalized excitations of DNA

Unmatched opportunities for novel nanoscale technologies and applications are provided by deoxyribonucleic acid (DNA). In this paper, we propose a quantum mechanical investigation into the optical excitations of DNA using calculations based on time-dependent density functional theory. Our findings demonstrate that DNA exhibits photoabsorption in the ultraviolet region of the electromagnetic spectrum, and transition contribution maps demonstrate that the optical transitions of DNA contain both localized and delocalized excitations. Additionally, we simulated and contrasted the electronic circular dichroism (ECD) spectra of B-DNA (a right-handed double helical structure) and Z-DNA (a left-handed double helical structure). We discovered significant variations in the ECD spectra. The design of DNA-based nano-optical devices should benefit from the theoretical findings in this work.