Energy and Lifetime of Temporary Anion States of Uracil by Stabilization Method

Abstract

To investigate the temporary anion states of uracil, density functional theory with asymptotically corrected potentials is adopted. The stabilized Koopmans' theorem and stabilized Koopmans-based approximation are used in conjunction with an analytic continuation procedure to calculate its resonance energies and lifetimes. Results indicate the presence of several low-lying π* and σ* temporary anion states of uracil. The characteristics of these resonance orbitals are also analyzed. By comparing them with the experimental values and theoretical calculations, it is believed that the stabilization approach can provide more information on the resonance states.

The benzene radical anion: A computationally demanding prototype for aromatic anions

“…The metastability of the benzene anion, and thus the applicability of standard wave function L 2 methods to this problem, is tested using the stabilization method. [38][39][40][41][42][43][44][45][46][47][48][49][50][51] As is commonly done to implement the stabilization method, the lowest roots of an eigenvalue problem for a specific state are tracked by smoothly varying the exponent of diffuse functions on each atom. Resonance parameters can then be extracted by analytically continuing the obtained energies into the complex plane.…”

Shape and core‐excited resonances of thionucleobases

“…In basis set I, only the orbital exponents of “++” functions will be multiplied by η. Since our previous calculations have shown that this basis set is flexible enough to characterize the TASs of uracil and halopyrimidines, all of our stabilization computations will be based on basis set I. Basis set II denotes the 6–311G(d,p) basis set for H, C, N, and O atoms and the 6–311G(3d,p) basis set for S atom.…”

“…In the present study, ωB97XD of LC‐DFT in conjunction with the SKT (SKT ωB97XD) and TD‐ωB97XD of TDDFT in conjunction with SM (S‐TD‐ωB97XD) will be adopted due to their superior calculated AEs in the studies of various molecules . In addition, S‐EA SAC‐CI is also adopted for comparison.…”

“…When density functional theory (DFT) is used, the adoption of long range corrected (LC) potentials is required to properly estimate the energies of TASs . By combining the aforementioned SM and LC potentials, we have introduced a stabilized Koopmans theory (SKT) in the framework of LC‐DFT in the study of SRs for various molecules . As for CERs, we have introduced the stabilized long range corrected time‐dependent density functional theory (S‐LC‐TDDFT) in the studies of p‐benzoquinone and halopyrimidines .…”

Exploring the metastability and the pathways for polyanionic isomerization in the dianions and trianions of doubly- and triply-deprotonated benzene

“…However, as evident from the charge stabilization plots in Fig. 1, the dianions and trianions being investigated can be stabilized relative to their parent anions and dianions, respectively, suggesting that the dianions of the doublydeprotonated benzene can be metastable in the sense of temporary anions, the confirmation of which though also requires measurement of the lifetime of the metastable states, for example, using the orbital exponent stabilization method [43][44][45]. In the present study, the tunneling lifetime for the electron loss is approximately estimated using a Coulomb model [9], discussed later in the article.…”