theory vs sptheory
Clicked A Few Times
3:25:53 PM PDT - Wed, Sep 7th 2016
I am new to ab initio calculations so I am still a bit hazy on some of the finer details, but in the DirDyVtSt module there is theory and sptheory and I was wondering, what is the difference?

Thanks

Forum Regular
5:47:08 AM PDT - Thu, Sep 8th 2016
The sptheory option is specific to dirdyvtst and allows the user to specify an additional (usually higher) level of theory to do single point calculations in addition to the regular set of calculations for dirdyvtst, see http://nwchemgit.github.io/index.php/Release66:Interface for more information

Clicked A Few Times
6:43:15 AM PDT - Thu, Sep 8th 2016
So is the theory level in which the reaction path is calculated typically performed using a lower level basis set. For example you would use 6-311g** for the initial geometry optimization and single point energy and 3-21g to calculate points along the reaction path. Is this correct?

Forum Regular
12:11:36 PM PDT - Thu, Sep 8th 2016
I think the idea is more that you calculate the reaction path at one level and then are interested in energies along that path at a higher level that would not be practical/affordable to calculate the reaction path with. But I could be wrong as I am not familiar with this dirdyvtst module or the program that it generates an input file for. My answer was based solely on a quick reading of the documentation page I linked above.


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