Nexus: Rework physical_system.py

nexus/nexus/gamess.py

@@ -154,7 +154,7 @@ def incorporate_result(self,result_name,result,sim):
                     self.block()
                 #end if
                 guess_inputs = obj()
-                ecounts = self.system.particles.electron_counts()
+                ecounts = self.system.electrons.n_up_down()
                 orbs = result.orbitals
                 order_map = obj(up='iorder',down='jorder')
                 nelec_map = obj(up=ecounts[0],down=ecounts[1])

nexus/nexus/gamess_input.py

@@ -1091,7 +1091,7 @@ def generate_any_gamess_input(**kwargs):
         # allow user override of charge and multiplicity from physical system
         gi.contrl.set_optional(
             icharg = system.net_charge,
-            mult   = system.net_spin+1,
+            mult   = system.electrons.multiplicity,
             )
         s = system.structure
         if s.has_folded():

nexus/nexus/periodic_table.py

@@ -7,6 +7,7 @@
 from __future__ import annotations
 from dataclasses import dataclass
 from enum import Enum
+from typing import TypeAlias
 from .developer import warn
 
 
@@ -578,3 +579,11 @@ def num_elements() -> int:
     Ts = Tennessine
     Og = Oganesson
 #end class Element
+
+
+ElementLike: TypeAlias = Elements | str | int
+"""Types that could be valid identifiers for an element.
+
+For example, an element's name or atomic symbol (``str``), or the
+element's atomic number (``int``), or a member of the ``Elements`` enum.
+"""