Isotopes with OpenMolcas

[ramess101]

I would like to investigate isotopic effects using SHARC and OpenMolcas. For this reason, I am trying to follow the "Specialized Tutorials" Section 3.1. The explanation for wigner.py is clear, but I am having issues with this step for modifying the input file:

I tried modifying my input file accordingly by adding ISOTOPES to GATEWAY:

But received the following error:

Unfortunately, although SHARC is intended for OpenMolcas v18, I believe I am seeing this error because v18 does not support isotopes. From what I can tell, OpenMolcas v19 or newer is required to provide Isotopes as a keyword to GATEWAY. This raises a few questions:

1. Have you successfully implemented this specialized tutorial with OpenMolcas v18?
2. Do you know if SHARC is compatible with OpenMolcas v19?
3. Other than what is provided in the tutorial, are there any other steps to be aware of to investigate isotope effects?

[MaxParadiz]

I have ran some (apparently) succesfull surface hopping with Molcas 19, but I have not done enough tests to know for sure whether it is fully compatible.

To make it compatible:
In SHARC_MOLCAS.py

line 876
allowedrange=[ (18.0,18.999), (8.29999,8.30001) ]
to
allowedrange=[ (18.0,19.999), (8.29999,8.30001) ]

And
line 2603
string+='R02O\nRELINT\nEXPERT\n'

to
string+='Relativistic = R02O\nRELINT\nEXPERT\n'

Hope this works for you.

[ramess101]

Thank you @MaxParadiz Somehow I was never notified of your response. I will try this.

[ramess101]

@MaxParadiz I just wanted to confirm that your recommendation worked for me. Thanks! I was able to complete the entire SHARC tutorial using OpenMolcas v19.11 with the N-15 isotope.

The only difference between my results and those in the tutorial was for what the "show" command displays within wigner.py.

The tutorial suggests the displayed mass will be in the same units that the user provides as input:

Whereas my experience was that SHARC converts the units of this mass before displaying it back to the user:

This is due to line 560 in wigner.py:

But having looked through wigner.py, I do not believe this is a problem because the same conversion (U_to_AMU) is used for the hard-coded default isotope masses as well. Specifically, the mass that is printed out to the geom file for the subsequent trajectory runs appears to be in the correct units (i.e., mass for N is 15). I just thought you might want to be aware of this since it is somewhat confusing to the user at first glance.

Thanks again!