Transition state optimisation


Am trying to a transition state optimization problem for the isomerization reaction, cis-HCNH -> trans-HCNH, with no success. psi4 returns : unable to compute torsion value
Optimizer: Optimization failed! (I tried several geometry guesses but none was successful).

Am I doing something wrong? Any suggestions/pointers


Here is the psi4 input

#cis to trans transition state optimization

molecule {
0 2
C 0.000000 0.000000 0.000000
N 0.000000 0.000000 1.440000
H 1.026720 0.000000 -0.362996
H -0.475176 0.823029 1.776000
set {
basis 6-31G*
reference uhf
opt_type ts
#geom_maxiter 200


I just ran your calculation using the input you provided with no issues at all. I used psi4 v1.1.


Good to note it worked in v1.1. Am using v1.0 but let me upgrade and I will let you know how it goes.


It seem the conda build is not yet updated to v1.1. Trying to update psi4 in my anaconda environment returns no updates. Is there an alternative way of doing it?


conda update psi4
Fetching package metadata …
Solving package specifications: .

All requested packages already installed.

packages in environment at //anaconda/envs/python2:

psi4 1.0.0 py27_g6a9a71b psi4

1.1 release series conda packages are “hidden” on a subchannel until release. Issue one of these commands to get a 1.1-era package. Go ahead and create a new conda environment rather than updating or installing into your 1.0 environment.

Thanks for testing the input, @emaradzike!

Am now up and running with v1.1 thanks@loriab. Yes @emaradzike, the input
works in this new release. Thank you!