I'm doing an IRC calculation for the TS structure of the reaction of adenine with OH radical.Although the IRC (forward) ran successfully the IRC(reverce) is giving the above mentioned error.I tried increasing the no. of cycles.Even then the same error is coming.Can someone explain the reason for this?
# ub3lyp/6-31g(d,p) scrf=(iefpcm,solvent=water) scf=(maxcyc=2000) irc=
(calcfc,reverse,maxpoints=60,stepsize=20)