Fixes for #33

functions_scattering.py
 - added scattering_type function

classes_scattering.py
 - added energy_mev to setup_scatter for neutron energy
 - setup_scatter option wavelength_a changed to check scatteing_type, now updates energy correctly for neutron and electron wavelengths.
 - new version of magnetic_form_factor function that includes elements with oxidations states

 TODO:
  - add test cases for magnetic form factors

Author: DanPorter

Dans_Diffraction/__init__.py

@@ -31,8 +31,8 @@
 Diamond
 2017-2025
 
-Version 3.3.4
-Last updated: 12/04/2025
+Version 3.4.0
+Last updated: 05/08/2025
 
 Version History:
 02/03/18 1.0    Version History started.
@@ -85,6 +85,7 @@
 20/11/24 3.3.2  Added alternate option for neutron scattering lengths
 06/02/25 3.3.3  Added scattering options for polarised neutron and x-ray scattering. Thanks dragonyanglong!
 12/04/25 3.3.4  Improved superstructure calculations by fixing scale parameter
+05/08/25 3.4.0  Added custom atomic form factors and dispersion corrections
 
 Acknoledgements:
     2018        Thanks to Hepesu for help with Python3 support and ideas about breaking up calculations
@@ -112,6 +113,7 @@
     Sep 2024    Thanks to thamnos for suggestion to add complex neutron scattering lengths
     Oct 2024    Thanks to Lee Richter for pointing out the error in triclinic basis definition
     Dec 2024    Thanks to dragonyanglong for pointing out the error with magnetic neutron scattering
+    May 2025    Thanks to vbhartiya for suggestions about magnetic neutron scattering
 
 -----------------------------------------------------------------------------
    Copyright 2018-2025 Diamond Light Source Ltd.
@@ -166,8 +168,8 @@
            'Structures', 'Fdmnes', 'FdmnesAnalysis']
 
 
-__version__ = '3.3.3'
-__date__ = '2025/02/06'
+__version__ = '3.4.0'
+__date__ = '2025/08/05'
 
 
 # Build

Dans_Diffraction/classes_scattering.py

@@ -182,7 +182,7 @@ def __str__(self):
         #out += '  use m1m1 approx.: %s\n' % self._resonant_approximation_m1m1
         return out
 
-    def setup_scatter(self, scattering_type=None, energy_kev=None, wavelength_a=None,
+    def setup_scatter(self, scattering_type=None, energy_kev=None, energy_mev=None, wavelength_a=None,
                       powder_units=None, powder_pixels=None, powder_lorentz=None, powder_overlap=None,
                       int_hkl=None, specular=None, parallel=None, theta_offset=None,
                       min_theta=None, max_theta=None, min_twotheta=None, max_twotheta=None,
@@ -217,13 +217,21 @@ def setup_scatter(self, scattering_type=None, energy_kev=None, wavelength_a=None
         """
 
         if scattering_type is not None:
-            self._scattering_type = scattering_type
+            self._scattering_type = fs.get_scattering_type(scattering_type)
 
         if energy_kev is not None:
             self._energy_kev = energy_kev
 
+        if energy_mev is not None:
+            self._energy_kev = energy_mev * 1e-6
+
         if wavelength_a is not None:
-            self._energy_kev = fc.wave2energy(wavelength_a)
+            if 'neutron' in self._scattering_type:
+                self._energy_kev = fc.neutron_energy(wavelength_a) * 1e-6  # meV
+            elif 'electron' in self._scattering_type:
+                self._energy_kev = fc.electron_energy(wavelength_a) * 1e-3  # eV
+            else:
+                self._energy_kev = fc.wave2energy(wavelength_a)
 
         if powder_units is not None:
             self._powder_units = powder_units

Dans_Diffraction/functions_scattering.py

@@ -39,13 +39,14 @@
 Diamond
 2018
 
-Version 1.0
-Last updated: 06/02/25
+Version 1.1
+Last updated: 05/08/25
 
 Version History:
 11/11/18 0.1    Version History started.
 13/07/21 0.9    Functions re-written and tested
 06/02/25 1.0    Removed refrences to unpolarised magnetic scattering due to incorrect averaging
+05/08/25 1.1    Added custom scattering option
 
 @author: DGPorter
 """
@@ -838,6 +839,15 @@ def scatteringvectors(q, energy_kev, azi_ref_q=(1, 0, 0), psi=0, polarisation='s
 ########################################################################################################################
 
 
+def get_scattering_type(scattering_type):
+    """Return correct label for scattering type"""
+    scattering_type = scattering_type.lower()
+    for name, alt_names in SCATTERING_TYPES.items():
+        if scattering_type in alt_names:
+            return name
+    raise Exception(f"Scattering type {scattering_type} not recognized")
+
+
 def get_scattering_function(scattering_type):
     """
     Return function for given scattering type

tests/test_data_tables.py

@@ -59,6 +59,11 @@ def test_old_new_functions():
     assert diff < 10, f"resonant scattering factors are incorrect"
 
 
+def test_magnetic_form_factor():
+    # TODO: add tests
+    assert True
+
+
 def test_custom_scattering_factor():
     coefs = (12.2841, 4.5791, 7.4409, 0.6784, 4.2034, 12.5359, 2.2488, 72.1692, 1.1118, 0.)
     table = np.array([

tests/test_structure_factors.py

@@ -95,3 +95,8 @@ def test_magnetic_mno():
         polarisation_vector=[1, 0, 0]
     )
     assert abs(xtl.Scatter.intensity([1, 1, 1]) - 4332.39) < 0.01, 'incorrect polarised neutron intensity'
+
+
+def test_magnetic_neutron():
+    # TODO: test against SF from https://taro-nakajima.github.io/fcal-n/
+    assert True