  If matter absorbs a photon of sufficient energy it emits an electron. The
question of the duration of the emission process has intrigued scientists for
decades. With the advent of attosecond metrology, experiments addressing such
ultrashort intervals became possible. While these types of studies require
attosecond experimental precision, we present here a novel measurement approach
that avoids those experimental difficulties. We instead extract the emission
delay from the interference pattern generated as the emitted photoelectron is
diffracted by the parent ion's potential. Targeting core electrons in CO, we
measured a 2d map of photoelectron emission delays in the molecular frame over
a wide range of electron energies. The measured emission times depend
drastically on the emission direction and exhibit characteristic changes along
the shape resonance of the molecule. Our approach can be routinely extended to
other electron orbitals and more complex molecules.
