Alignment of the hydrogen molecule under intense laser fields.

Area of Science:

• Molecular Physics
• Quantum Chemistry
• Laser Spectroscopy

Background:

• The E,F state of H2 is crucial for understanding molecular alignment.
• Molecular alignment is sensitive to external fields and intrinsic properties.

Purpose of the Study:

• To investigate the alignment of the electronically excited E,F state of H2.
• To quantify the polarizability anisotropy of the H2 (E,F J=0) state.

Main Methods:

• Velocity mapping imaging technique.
• Two-photon excitation of H2 to the (E,F; ν = 0, J = 0) state.
• Analysis of photofragment H+ images and angular distributions.

Main Results:

• Observed strong laser intensity dependence in H+ photofragment images.
• Identified interference between J=0 and Stark-mixed J=2 rovibrational states.
• Quantified the polarizability anisotropy of H2 (E,F J=0) as 312 ± 82 a.u. (46 ų).

Conclusions:

• The H2 (E,F) state exhibits high polarizability anisotropy, enabling significant molecular alignment.
• Achieved the most easily aligned molecule measured to date.
• Demonstrated a method for creating highly anisotropic superposition states for molecular alignment studies.