Observation of full contrast icosahedral Bose-Einstein statistics in laser desorbed, buffer gas cooled C$_{60}$

TL;DR

This study observes the quantum rotational behavior of C60 molecules cooled with buffer gas, revealing symmetry-induced spectral effects and demonstrating a laser desorption method that minimizes heat transfer, enabling lower temperature cooling.

Contribution

It introduces a laser desorption technique for buffer gas cooling of C60, allowing observation of full rotational spectra and symmetry effects previously unseen.

Findings

Complete rotational progression observed for J=0-29

Certain transitions disappear due to icosahedral symmetry

Laser desorption reduces heat transfer by 1000-fold

Abstract

The quantum mechanical nature of spherical top molecules is particularly evident at low angular momentum quantum number J. Using infrared spectroscopy on the 8.4$\mu$m rovibrational band of buffer gas cooled $^{12}$C$_{60}$, we observe the hitherto unseen R(J = 0 - 29) rotational progression, including the complete disappearance of certain transitions due to the molecule's perfect icosahedral symmetry and identical bosonic nuclei. The observation of extremely weak C$_{60}$ absorption is facilitated by a laser desorption C$_{60}$ vapor source, which transfers 1000-fold less heat to the cryogenic buffer gas cell than a traditional oven source. This technique paves the way to cooling C$_{60}$ and other large gas phase molecules to much lower temperatures, providing continued advances for spectral resolution and sensitivity.