Add docs for GMTKN55

Author: ElliottKasoar

docs/source/user_guide/benchmarks/index.rst

@@ -10,3 +10,4 @@ Benchmarks
     supramolecular
     physicality
     molecular_crystal
+    molecular

docs/source/user_guide/benchmarks/molecular.rst

@@ -0,0 +1,83 @@
+=================
+Molecular Systems
+=================
+
+GMTKN55
+=======
+
+Summary
+-------
+
+Performance in evaluating gas-phase chemical accuracy for main group thermochemistry,
+kinetics and noncovalent interactions, through 55 test sets, totalling 1,505 relative
+energies, categorised into five chemical domains.
+
+
+Metrics
+-------
+
+1. Small systems
+
+Weighted mean absolute deviation (MAD) of basic properties, such as atomic energies,
+ionisation potentials, and electron affinities, of small systems.
+
+For each system, the relative energy is calculated and compared to the reference
+energy. The MAD is calculated for each of the subsets within this category, including
+only neutral singlet systems. A weighted sum is calculated by multiplying each subset
+error by a weight and the number of systems in the subset. This is divided by the total
+number of systems within these subsets.
+
+2. Large systems
+
+Weighted mean absolute deviation (MAD) of reaction energies of large systems and
+isomerisation energies.
+
+Same as (1), for the appropriately categorised subsets.
+
+3. Barrier heights
+
+Weighted mean absolute deviation (MAD) of reaction barrier heights for transition state
+energetics for fundamental organic reactions.
+
+Same as (1), for the appropriately categorised subsets.
+
+4. Intramolecular NCIs
+
+Weighted mean absolute deviation (MAD) of intramolecular noncovalent interactions for
+conformational energetics and hydrogen bonding.
+
+Same as (1), for the appropriately categorised subsets.
+
+5. Intermolecular NCIs
+
+Weighted mean absolute deviation (MAD) of intermolecular noncovalent interactions for
+dimers, clusters, and host-guest complexes.
+
+
+5. All (WTMAD)
+
+Weighted mean absolute deviation (MAD) of all subsets.
+
+Same as (1), for all subsets.
+
+
+Computational cost
+------------------
+
+Low: tests are likely to take minutes to run on CPU.
+
+
+Data availability
+-----------------
+
+Input structures:
+
+* L. Goerigk, A. Hansen, C. Bauer, S. Ehrlich, A. Najibi, and S. Grimme, A look at the
+  density functional theory zoo with the advanced gmtkn55 database for general main
+  group thermochemistry, kinetics and noncovalent interactions, Physical Chemistry
+  Chemical Physics 19, 32184 (2017).
+
+Reference data:
+
+* Same as input data
+* PBE-D3(BJ)