utils_5.md

layout	title	parent	grand_parent	nav_order	toc	summary	permalink
default	Calculate <i>S</i><sub>msRRHO</sub>	Utility Tools	Examples and Guides	5	false	How to calculating an <i>averaged</i> <i>S</i><sub>msRRHO</sub> for CREST's entropy mode.	/page/examples/utilities/utils_5.html

{{page.title}}

{: .no_toc }

{{ page.summary }} {: .fs-6 .fw-300 }

---

Calculating an averaged S_msRRHO

In Chem. Sci., 2021, 12, 6551-6568 the conformational entropy is calculated as

$$ S_\text{conf} = S'\text{conf} + \bar{S}\text{msRRHO} $$

where $$S'_\text{conf}$$ is the conformational term proportional to the Gibbs-Shannon entropy, and the averaged S_msRRHO is obtained as

$$ \bar{S}\text{msRRHO} = \sum_i^\text{ensemble} p_i S{\text{msRRHO},i} - S_{\text{msRRHO},0} $$

The averaged S_msRRHO is an ensemble average over all S_msRRHO contributions for each conformer. Note that the S_msRRHO entropy for the input structure, S_msRRHO,0 is substracted here in order to make the entire term S_conf an additive correction to the DFT-based molecular entropy. {: .test-justify }

The averaged S_msRRHO can be calculated in a standalone application of CREST, similar to the --mdopt and --screen commands. The respective calculation can be invoked by the --rrhoav command.

{{ site.data.icons.code }} command {{ site.data. icons.codefile}} input-ensemble.xyz {{ site.data. icons.checkfile}} output

{% include command.html cmd='crest --rrhoav input-ensemble.xyz' %}

{% capture inputfile %}

{% endcapture %} {% include codecell.html content=inputfile style="font-size:10px" %}

{% capture outputfile %}

{% endcapture %} {% include codecell.html content=outputfile style="font-size:10px" %}

{% include defaulttab.html id="open-1" %}