Coherent Preparation of Highly Vibrating and Rotating D Molecules.

Highly vibrationally and rotationally excited hydrogen molecules are of immense interest for understanding and modeling the physics and chemistry of the cold interstellar medium. Using a sequence of two Stark-induced adiabatic Raman passages, we demonstrate the preparation of rotationally excited D molecules in the fourth excited vibrational level within its ground electronic state. The nearly complete population transfer to the target state is confirmed by observing both the threshold behavior as a function of the laser power and the depletion of the intermediate level. The vibrational excitation reported here opens new possibilities in the study of the much debated four-center reaction between a pair of hydrogen molecules. Additionally, these rovibrationally excited molecules could be potentially used to generate the high-intensity D ion beams considered essential for D-T thermonuclear fusion by enhancing the cross section for dissociative electron attachment by 5 orders of magnitude compared to that of the ground state.