Ab initio molecular orbital calculations of DNA radical ions. 5. Scaling of calculated electron affinities and ionization potentials to experimental values
- Oakland Univ., Rochester, MI (United States)
- Wayne State Univ., Detroit, MI (United States)
Ab initio molecular orbital calculations of the electron affinities (EAs) and ionization potentials (IPs) of the DNA bases are presented in this work. Comparisons of calculated and experimental values are made for a series of compounds of size and/or structure similar to the DNA bases. Excellent correlations between calculated and experimental values are found for both Koopmans EAs at the 6-31G[sup *] and D95v levels and calculated vertical EAs of the model compounds. Several basis sets are considered: 6-31G[sup *], 6-31+G(d), and D95v. Calculations at 6-31G[sup *] and 6-31+G(d) using both ROHF and ROMP2 theories show a consistent difference between calculated vertical and adiabatic EAs. This allows for a good estimate of DNA base adiabatic EAs. i.e., -0.7, -0.3, 0.2, 0.3, and 0.4 eV; from the vertical EAs -1.23, -0.74, -0.40, -0.32, and -0.19 eV for G, A, C, T, and U respectively. While EAs must be scaled, we find that Koopmans IPs calculated at the simple 3-21G level predict vertical IPs of the DNA bases with only a 0.15 eV average absolute deviation from the experimentally reported values and calculations at MP2/6-31+G(d)//6-31G[sup *] for the adiabatic ionization potentials of the DNA bases are all within 0.1 eV of experiment. 41 refs., 2 figs., 5 tabs.
- OSTI ID:
- 6628758
- Journal Information:
- Journal of Physical Chemistry; (United States), Vol. 99:3; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
59 BASIC BIOLOGICAL SCIENCES
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
DNA
AFFINITY
IONIZATION POTENTIAL
ORGANIC COMPOUNDS
COMPUTER CALCULATIONS
IONS
MOLECULAR ORBITAL METHOD
NUMERICAL DATA
RADICALS
CALCULATION METHODS
CHARGED PARTICLES
DATA
INFORMATION
NUCLEIC ACIDS
400201* - Chemical & Physicochemical Properties
550200 - Biochemistry
990200 - Mathematics & Computers