diff --git a/t3/schema.py b/t3/schema.py
index d2d9c646..89879602 100644
--- a/t3/schema.py
+++ b/t3/schema.py
@@ -488,14 +488,15 @@ def check_model(cls, value):
     @validator('pdep')
     def check_pdep_only_if_gas_phase(cls, value, values):
         """RMG.pdep validator"""
-        if value is not None and values['reactors'] is not None:
-            reactor_types = set([reactor['type'] for reactor in values['reactors']])
+        if value is not None and 'reactors' in values and values['reactors'] is not None:
+            reactor_types = set([reactor.type for reactor in values['reactors']])
             if value is not None and not any(['gas' in reactor for reactor in reactor_types]):
                 raise ValueError(f'A pdep section can only be specified for gas phase reactors, got: {reactor_types}')
         return value
 
     @root_validator(pre=True)
     def check_species_and_reactors(cls, values):
+        """Check species and reactors"""
         if 'reactors' in values and values['reactors'] is not None \
                 and 'species' in values and values['species'] is not None:
             # check species attributes (balance, solvation) make sense
@@ -584,6 +585,19 @@ def check_qm(cls, value):
         """InputBase.qm validator"""
         return value or dict()
 
+    @validator('rmg', always=True)
+    def check_rmg(cls, value):
+        """InputBase.rmg validator"""
+        # Check the presence of at least one inert gas if PDep is requested
+        if value.species and value.pdep and value.pdep.method:
+            for species in value.species:
+                if not species.reactive:
+                    break
+            else:
+                raise ValueError(f'Pressure Dependence calculations require at least one inert (non-reacting) '
+                                 f'species for the bath gas.')
+        return value
+
     @root_validator(pre=True)
     def validate_rmg_t3(cls, values):
         """InputBase.validate_rmg_t3"""
diff --git a/t3/utils/writer.py b/t3/utils/writer.py
index c5e6573c..11c8bd30 100644
--- a/t3/utils/writer.py
+++ b/t3/utils/writer.py
@@ -233,7 +233,7 @@ def write_rmg_input_file(rmg: dict,
                                                          )
 
     # pressureDependence
-    pdep = rmg['pdep']
+    pdep = rmg['pdep'].copy()
     if pdep is not None:
         pdep_template = """
 pressureDependence(
@@ -246,9 +246,10 @@ def write_rmg_input_file(rmg: dict,
     maximumAtoms=${max_atoms},
 )
 """
-        pdep['method'] = METHOD_MAP[pdep['method']]
+        pdep['method'] = pdep['method'] if pdep['method'] in list(METHOD_MAP.values()) else METHOD_MAP[pdep['method']]
         pdep['T_min'], pdep['T_max'], pdep['T_count'] = pdep['T']
         pdep['P_min'], pdep['P_max'], pdep['P_count'] = pdep['P']
+        pdep['T_count'], pdep['P_count'] = int(pdep['T_count']), int(pdep['P_count'])
         del pdep['T']
         del pdep['P']
         if pdep['interpolation'] == 'PDepArrhenius':