Classical Wigner propagation for attosecond streaking of molecules

A semiclassical method to directly simulate the attosecond streaking spectra of molecules is introduced. The classical Wigner propagation
(CWP) method combines the first-order perturbation theory with respect to the XUV pump field with the classical Wigner propagation of the ionized electron in the IR probe field. Comparison with numerically exact solutions of the Schroedinger equation for hydrogen and helium and with experimental data for helium suggest that the CWP accurately reproduces relative streaking delays. The method is applied to interpret experimental stereo-streaking delays of carbon monoxide and to predict the isotropic gas-phase streaking delays of the 3d orbital in ethyl bromide.