code: def use_pcm(self, pcm_params=None, solvent_key="solvent", solvent_params=None,
                  radii_force_field=None):
          
          self.params["pcm"] = dict()
          self.params[solvent_key] = dict()
          default_pcm_params = {"Theory": "SSVPE",
                                "vdwScale": 1.1,
                                "Radii": "UFF"}
          if not solvent_params:
              solvent_params = {"Dielectric": 78.3553}
          if pcm_params:
              for k, v in pcm_params.items():
                  self.params["pcm"][k.lower()] = v.lower() \
                      if isinstance(v, str) else v
  
          for k, v in default_pcm_params.items():
              if k.lower() not in self.params["pcm"].keys():
                  self.params["pcm"][k.lower()] = v.lower() \
                      if isinstance(v, str) else v
          for k, v in solvent_params.items():
              self.params[solvent_key][k.lower()] = v.lower() \
                  if isinstance(v, str) else copy.deepcopy(v)
          self.params["rem"]["solvent_method"] = "pcm"
          if radii_force_field:
              self.params["pcm"]["radii"] = "bondi"
              self.params["rem"]["force_fied"] = radii_force_field.lower()
docs: Set the solvent model to PCM. Default parameters are trying to comply to
          gaussian default value
  
          Args:
              pcm_params (dict): The parameters of "$pcm" section.
              solvent_key (str): for versions < 4.2 the section name is "pcm_solvent"
              solvent_params (dict): The parameters of solvent_key section
              radii_force_field (str): The force fied used to set the solute
                  radii. Default to UFF.