Fix: qe/pw/scf unit conversion is not consistent with dpdata (#725)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Introduced a configuration file for sodium SCF calculations, enhancing
quantum mechanical simulations.
- Added a new test class to verify properties of sodium systems,
improving test coverage.

- **Bug Fixes**
- Improved logic for block extraction and stress block handling to
enhance robustness.

- **Tests**
- Updated energy validation method to use relative comparisons for more
accurate results.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Han Wang <[email protected]>
Co-authored-by: Han Wang <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

dpdata/qe/scf.py

@@ -7,9 +7,13 @@
 
 from dpdata.utils import open_file
 
-ry2ev = 13.605693009
-bohr2ang = 0.52917721067
-kbar2evperang3 = 1e3 / 1.602176621e6
+from .traj import (
+    kbar2evperang3,
+    ry2ev,
+)
+from .traj import (
+    length_convert as bohr2ang,
+)
 
 _QE_BLOCK_KEYWORDS = [
     "ATOMIC_SPECIES",

tests/test_qe_pw_scf.py

@@ -161,11 +161,11 @@ def test_virial(self):
 
     def test_energy(self):
         ref_energy = -219.74425946528794
-        self.assertAlmostEqual(self.system_ch4.data["energies"][0], ref_energy)
+        self.assertAlmostEqual(self.system_ch4.data["energies"][0] / ref_energy, 1.0)
         ref_energy = -30007.651851226798
-        self.assertAlmostEqual(self.system_h2o.data["energies"][0], ref_energy)
+        self.assertAlmostEqual(self.system_h2o.data["energies"][0] / ref_energy, 1.0)
         ref_energy = -219.7153691367526562
-        self.assertAlmostEqual(self.system_ch4_2.data["energies"][0], ref_energy)
+        self.assertAlmostEqual(self.system_ch4_2.data["energies"][0] / ref_energy, 1.0)
 
 
 class TestPWSCFLabeledOutput(unittest.TestCase, TestPWSCFSinglePointEnergy):

tests/test_qe_pw_scf_energy_bug.py

@@ -8,7 +8,7 @@
 class TestPWSCFSinglePointEnergy:
     def test_energy(self):
         ref_energy = -296.08379065679094669
-        self.assertAlmostEqual(self.system_al.data["energies"][0], ref_energy)
+        self.assertAlmostEqual(self.system_al.data["energies"][0] / ref_energy, 1.0)
 
 
 class TestPWSCFLabeledOutput(unittest.TestCase, TestPWSCFSinglePointEnergy):