MENU ▼
Read by QxMD icon Read
search
OPEN IN READ APP
COMPARATIVE STUDY
JOURNAL ARTICLE

CASSCF/CAS-PT2 study of hole transfer in stacked DNA nucleobases

LluĂ­s Blancafort, Alexander A Voityuk
Journal of Physical Chemistry. A 2006 May 25, 110 (20): 6426-32
16706397
CASSCF and CAS-PT2 calculations are performed for the ground and excited states of radical cations consisting of two and three nucleobases. The generalized Mulliken-Hush approach is employed for estimating electronic couplings for hole transfer in the pi-stacks. We compare the CASSCF results with data obtained within Koopmans' approximation. The calculations show that an excess charge in the ground and excited states in the systems is quite localized on a single base both at the CASSCF level and in Koopmans' picture. However, the CASSCF calculations point to a larger degree of localization and, in line with this, smaller transition dipole moments. The agreement between the CAS-PT2 corrected energy gaps and the values estimated with Koopmans' theorem is better, with the CAS-PT2 calculations giving somewhat smaller gaps. Overall, both factors result in smaller CASSCF/CAS-PT2 couplings, which are reduced by up to 40% of the couplings calculated using Koopmans' approximation. The tabulated data can be used as benchmark values for the electronic couplings of stacked nucleobases. For the base trimers, comparison of the results obtained within two- and three-state models show that the multistate treatment should be applied to derive reliable estimates. Finally, the superexchange approach to estimate the donor acceptor electronic coupling in the stacks GAG and GTG is considered.

Comments

You need to log in or sign up for an account to be able to comment.

No comments yet, be the first to post one!

Related Papers

Available on the App Store

Available on the Play Store
Remove bar
Read by QxMD icon Read
16706397
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"