The Effect of Aqueous Medium on Nucleobase Shape Resonances: Insights from Microsolvation

We have studied the effect of microhydration on the anionic shape resonance states of uracil nucleobase. The resonance parameters were determined using the resonance via Padé approach along with the efficient wave function-based EA-EOM-DLPNO-CCSD method. Our results showed that the uracil resonances get stabilized with an increase in the extent of microsolvation. The energy of the resonances decreased, and the lifetime increased as the number of water molecules surrounding uracil was increased. Our calculation shows that ten water molecules are sufficient to make the lowest shape resonance of uracil a bound radical anionic state. It indicates that the lowest energy resonance state may become a bound state under bulk solvation.