Fantastic! Thanks for the clarification - I better understand the logic behind it now.
I tried it in a couple of systems and it seems to work fine.
I have also tried it on a transition state for a bisradical species and I got this error:
Traceback (most recent call last):
File "/home/ivan/mambaforge/envs/psi4_env/bin/psi4", line 338, in <module>
exec(content)
File "<string>", line 97, in <module>
File "/home/ivan/mambaforge/envs/psi4_env/lib//python3.9/site-packages/psi4/driver/driver.py", line 1272, in optimize
opt_object.take_step()
File "/home/ivan/mambaforge/envs/psi4_env/lib//python3.9/site-packages/optking/opt_helper.py", line 174, in take_step
self.dq, self.step_str = self.opt_manager.take_step(self.fq, self._Hq, self.E, return_str=True)
File "/home/ivan/mambaforge/envs/psi4_env/lib//python3.9/site-packages/optking/optimize.py", line 232, in take_step
achieved_dq, returned_str = self.opt_method.take_step(fq, H, energy, return_str=True)
File "/home/ivan/mambaforge/envs/psi4_env/lib//python3.9/site-packages/optking/IRCfollowing.py", line 97, in take_step
dq = self.dq_irc(fq, H)
File "/home/ivan/mambaforge/envs/psi4_env/lib//python3.9/site-packages/optking/IRCfollowing.py", line 212, in dq_irc
G_prime_root_inv = symm_mat_root(G_prime_inv)
File "/home/ivan/mambaforge/envs/psi4_env/lib//python3.9/site-packages/optking/linearAlgebra.py", line 171, in symm_mat_root
rootMatrix[i][i] = sqrt(evals[i])
ValueError: math domain error
Printing out the relevant lines from the Psithon --> Python processed input file:
core.set_global_option("IRC_STEP_SIZE", 0.25)
core.set_global_option("IRC_POINTS", 20)
core.set_global_option("IRC_DIRECTION", "forward")
core.set_global_option("CART_HESS_READ", "True")
core.set_global_option("FULL_HESS_EVERY", -1)
--> e, irc_forw = optimize('M06-2X-D3ZERO2B', molecule=irc_forwards, return_wfn=True)
irc_forwards.save_xyz_file('TS_radH_abstraction_primary_00_ircf.xyz',1)
core.set_global_option("IRC_STEP_SIZE", 0.25)
core.set_global_option("IRC_POINTS", 20)
core.set_global_option("IRC_DIRECTION", "backward")
core.set_global_option("CART_HESS_READ", "True")
!--------------------------------!
! !
! math domain error !
! !
!--------------------------------!
Psi4 stopped on: Thursday, 06 April 2023 05:43PM
Psi4 wall time for execution: 0:06:13.14
*** Psi4 encountered an error. Buy a developer more coffee!
*** Resources and help at github.com/psi4/psi4.
Do you think that this is something related to the system/PSI4 or something else?