Controlling The Alignment And Ionization/Dissociation Processes Of Ch₃I Molecules By Shaped Femtosecond Pulse

The ionization/dissociation process of molecules in laser field has been an important part of the study of subjects of atoms and molecules. With the development of the technology of ultra-short pulse shaping, people gradually take interesting in the impact of the special shape laser on ionization/dissociation process of molecular. This article uses the laser with a central wavelength of 800 nm, pulse duration of 90 fs and repetition rate of 1000 Hz. A sequence of evenly spaced pulses is generated by the sine phase function.We use the pulses of which the spacing between them is 210fs interact with the CH₃I molecule. We get distribution of the signal strength of ions with the laser polarization. We know that the alignment processes of CH₃I molecules by shaped femtosecond pulse is much better than the alignment processes of CH₃I molecules by transform limit pulse by using coulomb explosion methods. We propose several speculation of molecular alignment and the detection process on the molecular alignment,and the improvements on the experimental.We use a sequence of evenly spaced pulses interact with the CH₃I molecule. We received the relationship between the signal intensity of ions and the spacing between pulses and the relationship between the signal intensity of ions and theφwhich is the phase compensation parameters of sine phase function. We found the change of the signal intensity of ions with the spacing between pulses have the periodic oscillations. The change of the signal intensity of fragment ions withφhave a bimodal structure. We give a preliminary and qualitative explanation for the phenomenas above in frequency domain and time domain. Overall, we achieved the purpose of changing a different fragment ion yield by changing the shaping laser pulse with the same laser energy.