Allow molecular term symbol labels 1, 2, 3, etc.

xnx · Apr 25, 2022 · e7f9ccf · e7f9ccf
1 parent 50a2c08
commit e7f9ccf
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/src/pyvalem/states/molecular_term_symbol.py b/src/pyvalem/states/molecular_term_symbol.py
@@ -169,9 +169,16 @@
 molecule_term = (
     molecule_Smult + molecule_irrep + pp.Optional(pp.Suppress("_") + molecule_Omegastr)
 )
-term_label = pp.Combine(
+
+# Term Symbol label can be a single letter (perhaps followed by ' or ") ...
+term_label_let = pp.Combine(
     pp.Word(pp.srange("[A-Za-z]")) + pp.Optional(pp.oneOf(("'", '"')))
 ).setResultsName("term_label")
+# ... or a number. The open bracket is required but suppressed to distinguish
+# this type of term label from the spin multiplicity.
+term_label_num = integer.setResultsName("term_label") + pp.Suppress("(")
+term_label = term_label_let | term_label_num
+
 molecule_term_with_label = (
     pp.Optional(term_label)
     + pp.Suppress(pp.Optional("("))

diff --git a/tests/test_molecular_term_symbol.py b/tests/test_molecular_term_symbol.py
@@ -121,6 +121,13 @@ def test_molecular_term_symbol_repr(self):
         m4 = MolecularTermSymbol("4DELTA")
         self.assertTrue(repr(m3) == repr(m4) == "4Δ")
 
+    def test_term_symbol_label(self):
+        m1 = MolecularTermSymbol("1(2B1)")
+        self.assertEqual(repr(m1), "1(2B1)")
+        self.assertEqual(m1.term_label, "1")
+        self.assertRaises(MolecularTermSymbolError, MolecularTermSymbol, "1'(A\")")
+        self.assertRaises(MolecularTermSymbolError, MolecularTermSymbol, '-2(A")')
+
 
 if __name__ == "__main__":
     unittest.main()