Excited-State Energies and Electronic Couplings of DNA Base Dimers

Citations Over TimeTop 13% of 2010 papers

Abstract

The singlet excited electronic states of two pi-stacked thymine molecules and their splittings due to electronic coupling have been investigated with a variety of computational methods. Focus has been given on the effect of intermolecular distance on these energies and couplings. Single-reference methods, CIS, CIS(2), EOM-CCSD, TDDFT, and the multireference method CASSCF, have been used, and their performance has been compared. It is found that the excited-state energies are very sensitive to the applied method but the couplings are not as sensitive. Inclusion of diffuse functions in the basis set also affects the excitation energies significantly but not the couplings. TDDFT is inadequate in describing the states and their coupling, while CIS(2) gives results very similar to EOM-CCSD. Excited states of cytosine and adenine pi-stacked dimers were also obtained and compared with those of thymine dimers to gain a more general picture of excited states in pi-stacked DNA base dimers. The coupling is very sensitive to the relative position and orientation of the bases, indicating great variation in the degree of delocalization of the excited states between stacked bases in natural DNA as it fluctuates.

Related Papers

• → Experimental and computational study of the gas-phase interactions between lead(II) ions and two pyrimidic nucleobases: Uracil and thymine(2005)63 cited
• → Application of chromium‐doped fullerene as a carrier for thymine and uracil nucleotides: Comprehensive density functional theory calculations(2017)34 cited
• → DNA Nucleobase under Ionizing Radiation: Unexpected Proton Transfer by Thymine Cation in Water Nanodroplets(2020)3 cited
• → DNA Nucleobase Under Ionizing Radiation: Unexpected Proton Transfer by Thymine Cation in Water Nanodroplets(2020)
• → DNA Nucleobase Under Ionizing Radiation: Unexpected Proton Transfer by Thymine Cation in Water Nanodroplets(2020)