We discuss the distribution of ions around highly charged PEs when there is competition between monovalent and multivalent ions, pointing out that in this case the number of condensed ions is sensitive to short-range interactions, salt and model-dependent approximations. This sensitivity is discussed in the context of recent experiments on DNA aggregation, induced by multivalent counterions such as spermine and spermidine.
Bibliographical noteFunding Information:
We are grateful to E. Raspaud and J.-L. Sikorav for numerous discussions. Support from the US–Israel Binational Science Foundation (B.S.F.) under grant No. 287/02 and the Israel Science Foundation under grant No. 210/02 is gratefully acknowledged.
- Multivalent ions