**Describe the bug** For pvlib==0.9.5, when n = 1 (no reflection) and aoi > 90°, we get nan as result. **To Reproduce** ```python import pvlib pvlib.iam.physical(aoi=100, n=1) ``` returns `nan`. **Expected behavior** The result should be `0`, as it was for pvlib <= 0.9.4. **Versions:** - ``pvlib.__version__``: '0.9.5' - ``pandas.__version__``: '1.5.3' - python: 3.10.4