Towards Ultracold Organic Chemistry: Prospects of Laser Cooling Large Organic Molecules

Abstract

<jats:p>Ultracold organic chemistry enables studies of reaction dynamics and mechanisms in quantum regime. Access to ultracold molecules hinges on the ability to efficiently scatter&lt;br&gt;multiple photons via quasi-closed cycling transitions and, in practice, is complicated by the complex electronic structure of polyatomic molecules. Using equation-of-motion coupled-cluster (EOM-CC) calculations, we demonstrate that an alkaline earth metal attached to various aromatic ligands (such as benzene, phenol, cyclopentadienyl and pyrrolide) feature nearly-closed cycling transitions with only a few additional repump lasers. We also show that aromatic ligands such as benzene can accommodate multiple cycling centers in various geometrical configurations and may open new avenues in quantum information science, precision measurements, and ultracold chemistry.</jats:p>

On the prospects of optical cycling in diatomic cations: Effects of transition metals, spin-orbit couplings, and multiple bonds

“…We solve the electronic structure problem using high-level ab initio methods following the protocols from our previous studies on laser-coolable species. 1,40,41,43 We use the equationof-motion coupled-cluster method for electron attachment (EOM-EA-CC) to describe the ground and excited electronic states of doublet radical cations 50,51 . In these calculations the target states (with +1 charge) are obtained by attaching an electron to a closed-shell +2 reference state described by the coupled-clusters singles doubles (CCSD) method.…”

“…Their strategy has been later successfully exploited in laser-cooling of polyatomic neutral molecules [37][38][39] . Following this strategy, more polyatomic molecules were proposed as prospective candidates for laser cooling [40][41][42][43][44] .…”

On the prospects of optical cycling in diatomic cations: Effects of transition metals, spin-orbit couplings, and multiple bonds

“…This idea, first introduced by Isaev and Berger 36 , has led to successful laser-cooling of polyatomic neutral molecules [37][38][39] . Following this strategy, more polyatomic molecules were proposed as prospective candidates for laser cooling [40][41][42][43][44] .…”