diff --git a/rmgpy/rmg/main.py b/rmgpy/rmg/main.py
index 8291db4a13..6d0e610fca 100644
--- a/rmgpy/rmg/main.py
+++ b/rmgpy/rmg/main.py
@@ -614,23 +614,35 @@ def initialize(self, **kwargs):
 
         # Initialize reaction model
 
-        # Seed mechanisms: add species and reactions from seed mechanism
-        # DON'T generate any more reactions for the seed species at this time
-        for seed_mechanism in self.seed_mechanisms:
-            self.reaction_model.add_seed_mechanism_to_core(seed_mechanism, react=False)
-
         # Reaction libraries: add species and reactions from reaction library to the edge so
         # that RMG can find them if their rates are large enough
         for library, option in self.reaction_libraries:
             self.reaction_model.add_reaction_library_to_edge(library)
 
         # Also always add in a few bath gases (since RMG-Java does)
-        for label, smiles in [("Ar", "[Ar]"), ("He", "[He]"), ("Ne", "[Ne]"), ("N2", "N#N")]:
+        for label, smiles in [('Ar', '[Ar]'), ('He', '[He]'), ('Ne', '[Ne]'), ('N2', 'N#N')]:
             molecule = Molecule().from_smiles(smiles)
             spec, is_new = self.reaction_model.make_new_species(molecule, label=label, reactive=False)
             if is_new:
                 self.initial_species.append(spec)
 
+        for spec in self.initial_species:
+            submit(spec, self.solvent)
+
+        # Add nonreactive species (e.g. bath gases) to core first
+        # This is necessary so that the PDep algorithm can identify the bath gas
+        for spec in self.initial_species:
+            if not spec.reactive:
+                self.reaction_model.enlarge(spec)
+        for spec in self.initial_species:
+            if spec.reactive:
+                self.reaction_model.enlarge(spec)
+
+        # Seed mechanisms: add species and reactions from seed mechanism
+        # DON'T generate any more reactions for the seed species at this time
+        for seed_mechanism in self.seed_mechanisms:
+            self.reaction_model.add_seed_mechanism_to_core(seed_mechanism, react=False)
+
         # Perform species constraints and forbidden species checks on input species
         for spec in self.initial_species:
             if self.database.forbidden_structures.is_molecule_forbidden(spec.molecule[0]):
@@ -690,15 +702,6 @@ def initialize(self, **kwargs):
                 spec.get_liquid_volumetric_mass_transfer_coefficient_data()
                 spec.get_henry_law_constant_data()
 
-        # Add nonreactive species (e.g. bath gases) to core first
-        # This is necessary so that the PDep algorithm can identify the bath gas
-        for spec in self.initial_species:
-            if not spec.reactive:
-                self.reaction_model.enlarge(spec)
-        for spec in self.initial_species:
-            if spec.reactive:
-                self.reaction_model.enlarge(spec)
-
         # chatelak: store constant SPC indices in the reactor attributes if any constant SPC provided in the input file
         # advantages to write it here: this is run only once (as species indexes does not change over the generation)
         if self.solvent is not None: