Attosecond molecular spectroscopy -: The one-electron H2+ system

Numerical solutions of the time-dependent Schrodinger equation for a 1-D model non-Born-Oppenheimer H-2(+) are used to illustrate the nonlinear, nonperturbative response of molecules to intense (I greater than or equal to 10(13) W/cm(2)), ultrashort (t < 10 fs) laser pulses. Molecular high-order harmonic generation (MHOHG) is shown to be an example of such response, and the resulting nonlinear photon emission spectrum is shown to lead to the synthesis of single attosecond (10(-18) s) pulses. Application of such ultrashort pulses to the H-2(+) system results in localized electron wave packets whose motion can be detected by asymmetry in the photoelectron spectrum generated by a subsequent probe attosecond pulse, thus leading to measurement of electron motion in molecules on an attosecond time scale.