Overview of Reaction (IMAGE) Georgia Institute of Technology Caption The ionized 14-base pair oligomer of B-DNA [d(5'-AAGGAAGGAAGGAA-3')]/[d(3'-TTCCTTCCTTCCTT-5')], modeled in this study through a hybrid quantum/classical simulation method. The bold letters GG/CC in the middle of the sequence denote the region treated quantum mechanically (QM), where the ionization hole reside. The hole density, depicted in light blue, is superimposed on the QM region. In the background we show the water environment surrounding the DNA molecule. In the QM region the color assignments are as follows: P yellow, C green, N blue, O (base) red, O (phosphate) red, O (H2O) orange, H (H2O) small blue spheres, Na purple. Note that most of the counter ions are located in the vicinity of the phosphate groups, with one of the counter ions in the QM region residing in the major groove. Credit Uzi Landman/Georgia Tech Usage Restrictions Use only with the appropriate credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.