I am a first time undergraduate user of Psi4 and am trying to collect information on the potential energy vs dihedral plot of phenol. However, I keep getting problems with convergence at some dihedral angles, even after expanding the geom_maxiter to 250 steps. Additionally, when I try to add damping to my scf calculations, I still am unable to converge. I have copied my input file as well as my error messages and would appreciate your help!

molecule phenol {

0 1

C -1.40249 -0.06649 0.04385

C -0.76579 1.16517 0.00350

C 0.62963 1.22075 -0.05185

C 1.45228 0.08210 -0.06982

C 0.75327 -1.13575 -0.02720

C -0.64037 -1.22534 0.02850

O 2.72273 0.14823 -0.12041

H -2.43229 -0.12009 0.08486

H -1.31956 2.03594 0.01430

H 1.08021 2.14873 -0.08111

H 1.29850 -2.01190 -0.03759

H -1.10000 -2.14886 0.05806

H 3.14772 0.98287 -0.14750

}

set {

basis cc-pvdz

intrafrag_step_limit 0.1

}

set scf {

soscf_max_iter 35

basis_guess true

damping_percentage 30

}

dihedrals = [i for i in range(0,185, 5)]

PES = []

for phi in dihedrals:

my_string = "5 4 7 13 " + str(phi)

set optking geom_maxiter = 250

set optking fixed_dihedral = $my_string

print(phi)

E = optimize(‘scf’)

print(E)

PES.append((phi, E))

print("\n\tcc-pVDZ SCF energy as a function of phi\n")

for point in PES:

print("\t%5.1f%20.10f" % (point[0], point[1]))

And my error message is:

psi4.driver.p4util.exceptions.SCFConvergenceError: Could not converge SCF iterations in 100 iterations.

Please let me know if you have any questions or would like to see more of my output to better address this problem!