diff --git a/indica/bayesmodels.py b/indica/bayesmodels.py
index cdfa9fab..ccd5e636 100644
--- a/indica/bayesmodels.py
+++ b/indica/bayesmodels.py
@@ -173,6 +173,8 @@ def ln_posterior(self, parameters: dict, **kwargs):
         ln_posterior = ln_likelihood + ln_prior
 
         kin_profs = {
+            "Zeff": self.plasma.zeff.sel(t=self.plasma.time_to_calculate),
+            
             "electron_density": self.plasma.electron_density.sel(
                 t=self.plasma.time_to_calculate
             ),