Small fixes

src/rydstate/angular/angular_ket.py

@@ -292,21 +292,10 @@ def get_qn(self, qn: AngularMomentumQuantumNumbers, *, allow_unknown: bool | Non
         if qn in self.quantum_number_names:
             qn_value = getattr(self, qn)
         else:
-            for coupled_quantum_numbers in (
-                self.coupled_quantum_numbers,
-                AngularKetLS.coupled_quantum_numbers,
-                AngularKetJJ.coupled_quantum_numbers,
-                AngularKetFJ.coupled_quantum_numbers,
-            ):
-                if qn not in coupled_quantum_numbers:
-                    continue
-
-                qn_1, qn_2 = coupled_quantum_numbers[qn]
-                qn_1_value = self.get_qn(qn_1, allow_unknown=True)
-                qn_2_value = self.get_qn(qn_2, allow_unknown=True)
-                qn_value = try_trivial_spin_addition(qn_1_value, qn_2_value, None)
-                if not is_unknown(qn_value):
-                    break
+            coupling_scheme = get_coupling_scheme_for_quantum_number(qn)
+            state = self.to_state(coupling_scheme)
+            if state.calc_std_qn(qn) == 0:
+                qn_value = state.calc_exp_qn(qn)
 
         allow_unknown = self._allow_unknown if allow_unknown is None else allow_unknown
         if not allow_unknown and is_unknown(qn_value):

src/rydstate/rydberg_state/rydberg_ket.py

@@ -183,7 +183,7 @@ def core_state(self) -> RydbergStateSQDT[Any] | None:
 
         ion_species = f"{self.species}_ion"
         try:
-            ion_sqdt = get_sqdt(ion_species)
+            core_sqdt = get_sqdt(ion_species)
         except ValueError:
             logger.warning(
                 "No SQDT data available for the ion species of %s, "
@@ -198,14 +198,15 @@ def core_state(self) -> RydbergStateSQDT[Any] | None:
         if is_unknown(l_c) or is_unknown(j_c) or is_unknown(f_c):
             return None
 
-        angular_ket = AngularKetLS(l_r=l_c, j_tot=j_c, f_tot=f_c, species=ion_species)
+        # The core electron of the neutral atom is the valence electron of the ion, with total angular momentum j_c.
+        core_angular_ket = AngularKetLS(l_r=l_c, j_tot=j_c, f_tot=f_c, species=ion_species)
 
         # TODO: we should probably also store n_c for the core angular ket in the future
         # for now, it is correct to assume that the core electron is
         # in the lowest allowed shell of the ion for the given l_c
         for n_c in range(l_c + 1, l_c + 15):
-            if ion_sqdt.is_allowed_shell(n_c, l_c, 0.5):
-                return RydbergStateSQDT(ion_species, n_c, angular_ket=angular_ket, sqdt=ion_sqdt)
+            if core_sqdt.is_allowed_shell(n_c, l_c, 0.5):
+                return RydbergStateSQDT(ion_species, n_c, angular_ket=core_angular_ket, sqdt=core_sqdt)
 
         raise ValueError(f"No allowed shell found for ion species {ion_species} with l_c={l_c}.")
 

src/rydstate/species/strontium_ion/potential_data.py

@@ -18,15 +18,15 @@ class _PotentialMarinescu1994StrontiumIonAbstract(PotentialMarinescu1994):
     # Note that the potential there is defined with Marinescu a_j = Greene \alpha_i as follows:
     # a_1 = \alpha_1
     # a_2 = \alpha_3
-    # a_3 = \alpha_2
+    # a_3 = -\alpha_2 (Note the minus sign!)
     # and a_4 = 0
     alpha_c_marinescu_1994 = 7.5
     r_c_dict_marinescu_1994: ClassVar = {0: 1.7965, 1: 1.3960, 2: 1.6820, 3: 1.0057}
     model_potential_parameter_marinescu_1994: ClassVar = {
-        0: (3.4187, 1.5915, 4.7332, 0),
-        1: (3.3235, 1.5712, 2.2539, 0),
-        2: (3.2533, 1.5996, 3.2330, 0),
-        3: (5.3540, 5.6624, 7.9517, 0),
+        0: (3.4187, 1.5915, -4.7332, 0),
+        1: (3.3235, 1.5712, -2.2539, 0),
+        2: (3.2533, 1.5996, -3.2330, 0),
+        3: (5.3540, 5.6624, -7.9517, 0),
     }
 
 

tests/test_ion.py

@@ -1,4 +1,7 @@
+import logging
+
 import pytest
+from rydstate import RydbergStateSQDT
 from rydstate.species import get_element_properties, get_potential_class, get_sqdt
 from rydstate.species.element_properties import ElementProperties
 from rydstate.species.utils import calc_energy_from_nu, calc_nu_from_energy, get_all_subclasses
@@ -42,3 +45,38 @@ def test_ion_nist_data_is_loaded(species: str) -> None:
         assert (5, 2, 1.5, 0.5) in levels  # 4f14.5d 2D3/2
         # only doublets (s_tot = 1/2) since Yb+ is alkali-like (closed-shell 4f14 core)
         assert all(s_tot == 0.5 for (_n, _l, _j, s_tot) in levels)
+
+
+# Low-lying Sr+ states (n, l_r) whose energies come from the NIST data (no quantum defects are defined
+# for the ion, so nu is taken from the measured levels and the radial shape from the model potential).
+# The expected number of radial nodes of a state is n - l - 1.
+STRONTIUM_ION_LOW_LYING_STATES = [
+    (5, 0),  # 5s, ground state of Sr+
+    (6, 0),  # 6s
+    (7, 0),  # 7s
+    (5, 1),  # 5p
+    (6, 1),  # 6p
+    (4, 2),  # 4d
+    (5, 2),  # 5d
+    (4, 3),  # 4f
+]
+
+
+@pytest.mark.parametrize(("n", "l_r"), STRONTIUM_ION_LOW_LYING_STATES)
+def test_strontium_ion_radial_wavefunction(n: int, l_r: int, caplog: pytest.LogCaptureFixture) -> None:
+    """The integrated Sr+ wavefunction is normalized, has n - l - 1 nodes and raises no warnings."""
+    j_tot = l_r + 0.5
+    state = RydbergStateSQDT("Sr88_ion", n=n, l_r=l_r, j_tot=j_tot, f_tot=j_tot)
+    radial = state.radial
+
+    with caplog.at_level(logging.WARNING):
+        radial.integrate_wavefunction()
+
+    # No sanity-check (or any other) warning should be emitted during the integration.
+    warnings = [record.getMessage() for record in caplog.records if record.levelno >= logging.WARNING]
+    assert warnings == [], f"Unexpected warnings for Sr88_ion n={n} l={l_r}:\n" + "\n".join(warnings)
+
+    # The wavefunction is correctly integrated and normalized ...
+    assert radial.norm == pytest.approx(1.0)
+    # ... and has exactly n - l - 1 nodes with the (sign-corrected) model potential.
+    assert radial.nodes == n - l_r - 1