Hi allI am sujit, i am working with Gaussian-09 very recently(2months)/ can be described as a beginnner. I am very much using B3lyp hybrid-function for verious calculation such geometry opt, IRC, Scrf etc but recently i am facing problem with MO6 function for IRC calculation!!1)# MO6/6-311+G(d,p) IRC=(calcfc,maxcycle=1000) scf=(tight,maxcycle=1000,cdiis) showing me all the time syntax error!! can anyone tell me what kind of mistake I am making during my input command in the route section?2)# MO6/6-311+G(d,p) opt scf=(tight, cdiis) for Fe+3 complex, link died couple of times after 30min of run!! I do not know the reason behind it, though b3lyp gave nice results, anybody can suggest what will be the probable problem for this case?3)# MO6/6-311+G(d,p) opt=(calcall,maxcycle=600) scf=(tight,maxcycle=600,cdiis) Also I am having problem for frequency calculation using MO6, syntax error, please correct my mistake?Looking forward for suggestionsSujit