I need to optimize the C4-OH–adduct radical of Guanine.However when I insert charge=0 and multiplicity=2 and optimize, the no of electrons is similar to the anion not the radical.Please explain how to do this.
No, it's not similar. An anion would have (in most cases) charge = -1 and multiplicity = 1, since (in most cases) you only remove a proton to make it charged, but keep the no of electrons intact. A radical would have 0, 2 , as you correctly assumed. See http://www.cup.uni-muenchen.de/ch/compchem/tests/test188.com for a gaussian test with OH radical.
No, it's not similar. An anion would have (in most cases) charge = -1 and multiplicity = 1, since (in most cases) you only remove a proton to make it charged, but keep the no of electrons intact. A radical would have 0, 2 , as you correctly assumed. See http://www.cup.uni-muenchen.de/ch/compchem/tests/test188.com for a gaussian test with OH radical.