diff --git a/src/nmreval/models/basic.py b/src/nmreval/models/basic.py
index 6ce6c3b..98be0f8 100644
--- a/src/nmreval/models/basic.py
+++ b/src/nmreval/models/basic.py
@@ -224,9 +224,9 @@ class ExpFunc:
     @staticmethod
     def func(x, c, x0, beta, pm: int = -1, mode: str = 'time'):
         if mode == 'time':
-            return c * np.exp(np.sign(pm) * (x0 * x) ** beta)
-        elif mode == 'rate':
             return c * np.exp(np.sign(pm) * (x / x0) ** beta)
+        elif mode == 'rate':
+            return c * np.exp(np.sign(pm) * (x * x0) ** beta)
         else:
             raise ValueError('Unknown mode %s. Use either "rate" or "time".' % str(mode))