Bump rotor barrier threshold to 60 kJ/mol; fix multi-well warning

The 40 kJ/mol default was too tight for combustion-temperature rotors; 60 kJ/mol better fits hindered-rotor treatment at kT ≈ 8–17 kJ/mol. Also rewrite the multi-well "high barrier" warning, which was missing a noun ("has 2," -> "has 2 wells") and read as a run-on.

Author: alongd

arc/job/trsh.py

@@ -1715,13 +1715,12 @@ def scan_quality_check(label: str,
             logger.warning(message)
             return invalidate, invalidation_reason, message, actions
         else:
-            logger.warning(f'The maximal barrier for rotor {pivots} of {label} is '
-                           f'{(np.max(energies) - np.min(energies)):.2f} kJ/mol, which is higher than the set threshold '
-                           f'of {maximum_barrier} kJ/mol. Since this mode when treated as torsion has {num_wells}, '
-                           f'this mode is not invalidated: treating it as a vibrational mode will be less accurate than '
-                           f'the hindered rotor treatment, since the entropy contribution from the population of '
-                           f'this species at the higher wells will not be taken into account. NOT invalidating this '
-                           f'torsional mode.')
+            barrier_kJmol = np.max(energies) - np.min(energies)
+            logger.warning(f'Rotor {pivots} of {label}: barrier {barrier_kJmol:.2f} kJ/mol '
+                           f'exceeds the {maximum_barrier} kJ/mol threshold, but the mode has '
+                           f'{num_wells} wells. Keeping the hindered-rotor treatment — '
+                           f'demoting to a harmonic vibration would miss the entropic '
+                           f'contribution from the upper well(s).')
 
     if preserve_params is not None:
         success = True

arc/settings/settings.py

@@ -265,8 +265,8 @@
 rotor_scan_resolution = 8.0  # degrees. Default: 8.0
 
 # rotor validation parameters
-maximum_barrier = 40    # a rotor threshold (kJ/mol) above which the mode will be considered as vibrational if
-                        # there's only one well. Default: 40 (~10 kcal/mol)
+maximum_barrier = 60    # a rotor threshold (kJ/mol) above which the mode will be considered as vibrational if
+                        # there's only one well. Default: 60 (~14 kcal/mol)
 minimum_barrier = 1.0   # a rotor threshold (kJ/mol) below which it is considered a FreeRotor. Default: 1.0 kJ/mol
 inconsistency_az = 5    # maximum allowed inconsistency (kJ/mol) between initial and final rotor scan points. Default: 5
 inconsistency_ab = 0.3  # maximum allowed inconsistency between consecutive points in the scan given as a fraction