I can, but that's because I don't accept your definition of atheist.<quoted text>
You either believe in the possibility of the existence of deities or you don't.
If you do, you're agnostic.
If you don't, you're atheist.
You cannot be both.
I am an atheist that acknowledges the logical possibility of gods because I don't know how to exclude it if it is impossible.
I also believe that it may be possible to someday show that gods are impossible, whether by a logical argument, a mathematical argument, or empirical evidence. But not today, which makes me an agnostic.
I also reject all god claims to date, which makes me an atheist. My worldview is godless.