Theoretical investigation of the asymmetric molecular harmonic emission and the attosecond pulse generation.

The harmonic emission of the asymmetric charged molecule HeH(2+) ion is theoretically investigated by solving the one-dimensional-time-dependent Schrödinger equation. Results show that the laser-induced electron transfer process between the vibrational state and the ground electronic state is responsible for the resonant peak on the harmonic spectrum, and that the two ionization pathways are behind the two identified cutoff energies. In addition, by optimizing the asymmetric harmonic emission, the generations of the ultrashort attosecond pulses are also discussed.