Scheme for state-selective formation of highly rotationally excited diatomic molecules

Abstract

A scheme is proposed for making highly rotationally excited diatomic molecules (“super rotors”) in their ground vibrational and electronic state, e.g., 6Li2X 1Σg+ (v=0,J⩾115) where the rotational energy exceeds the bond strength (E(0,J)−E(0,0)⩾D00). Such levels, while strictly speaking quasibound, have very long tunneling lifetimes (>1011 s for J⩽130), and should have very interesting and unique collisional properties, especially at low temperature. The rotation of the molecules is “spun up” by sequential irradiation by R branch photons in the A 1Σu+–X 1Σg+ bands starting with cold molecules at low J. Spontaneous emission to other vibrational levels is overcome by using a pump laser and its multiple Raman sidebands as in previous work on “spinning down” diatomics.

Cold collisions of highly rotationally excited CO2with He: The prospects for cold chemistry with super-rotors

“…A related proposal was made by Li et al [10], but unlike the work of Refs. [8,9], which results in a distribution of rotational levels, their scheme would produce molecules in a single, selected j level.…”

“…Over the past decade, there has been an increasing interest in generating molecules in high rotational levels, so-called super-rotors [8][9][10]. An interesting aspect of super-rotors is their prospect to possess unique properties at very low temperatures.…”

Cold collisions involving rotationally hot oxygen molecules

“…Experimental schemes to produce diatomic molecules in highly excited rotational states have been proposed [1,2] and recently realized [3]. Theoretical studies have suggested that the collisional dynamics of such rotationally hot molecules would be particularly interesting at low temperatures [4][5][6][7][8].…”

Zero-Energy Resonances of Hydrogen Diatom Isotopologs: Tuning Quasiresonant Transitions in Vibration Space

“…The presence of a QRVR condition together with an ultralow collision energy can yield sharp structures in rotational distributions of total quenching rate coefficients [16][17][18] and may allow convenient detection for systems containing rotationally hot molecules [17][18][19]. While experimental schemes to form highly rotationally excited molecules have been proposed [20,21] and realized [22,23], most experimental approaches which produce translationally cold molecules, however, do not contain a significant population of rotationally excited states, so the interesting case of ultracold QRVR energy transfer has yet to be observed experimentally. Nevertheless, a very recent experimental study has demonstrated rotational excitation of translationally cold N 2 molecules [24].…”