diff --git a/doc/changelog.d/601.fixed.md b/doc/changelog.d/601.fixed.md
new file mode 100644
index 000000000..7b4b8e283
--- /dev/null
+++ b/doc/changelog.d/601.fixed.md
@@ -0,0 +1 @@
+coding error, switch to correct order
\ No newline at end of file
diff --git a/src/ansys/speos/core/bsdf.py b/src/ansys/speos/core/bsdf.py
index c7576ad51..96b069ec1 100644
--- a/src/ansys/speos/core/bsdf.py
+++ b/src/ansys/speos/core/bsdf.py
@@ -462,7 +462,7 @@ def __init__(self, speos: Speos, file_path: Union[Path, str] = None):
             self._brdf, self._btdf = self._extract_bsdf()
             self._has_transmission = bool(self._btdf)
             self._has_reflection = bool(self._brdf)
-            self._transmission_spectrum, self._reflection_spectrum = self._extract_spectrum()
+            self._reflection_spectrum, self._transmission_spectrum = self._extract_spectrum()
             try:
                 self._stub.GetSpecularInterpolationEnhancementData(Empty())
                 self.__interpolation_settings = InterpolationEnhancement(