diff --git a/atomistics/calculators/lammps/__init__.py b/atomistics/calculators/lammps/__init__.py
index 54f7493b..db52b874 100644
--- a/atomistics/calculators/lammps/__init__.py
+++ b/atomistics/calculators/lammps/__init__.py
@@ -19,11 +19,15 @@
     from atomistics.calculators.lammps.phonon import (
         calc_molecular_dynamics_phonons_with_lammps,
     )
+
+    __all__ = [
+        calc_molecular_dynamics_phonons_with_lammps,
+    ]
 except ImportError:
-    pass
+    __all__ = []
 
 
-__all__ = [
+__all__ += [
     calc_molecular_dynamics_thermal_expansion_with_lammps,
     calc_molecular_dynamics_nph_with_lammps,
     calc_molecular_dynamics_npt_with_lammps,
@@ -36,5 +40,4 @@
     optimize_positions_with_lammps,
     get_potential_dataframe,
     get_potential_by_name,
-    calc_molecular_dynamics_phonons_with_lammps,
 ]