Emulating optical cycling centers in polyatomic molecules

Ming Li,Alexander Petrov,Svetlana Kotochigova,Jacek Kłos

doi:10.1038/s42005-019-0245-2

Ming Li, Alexander Petrov + Show 2 more

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https://doi.org/10.1038/s42005-019-0245-2

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Abstract

An optical cycling center (OCC) is a recently coined term to indicate two electronic states within a complex quantum object that can repeatedly experience optical laser excitation and spontaneous decay, while being well isolated from its environment. Here we present a quantitative understanding of electronic, vibrational, and rotational excitations of the polyatomic SrOH molecule, which possesses a localized OCC near its Sr atom. In particular, we describe the vibrationally dependent trends in the Franck–Condon factors of the bending and stretching modes of the molecular electronic states coupled in the optical transition. These simulations required us to perform electronic structure calculations of the multi-dimensional potential energy surfaces of both ground and excited states, the determination of vibrational and bending modes, and corresponding Franck–Condon factors. We also discuss the extent to which the optical cycling center has diagonal Franck–Condon factors.

Highlights

An optical cycling center (OCC) is a recently coined term to indicate two electronic states within a complex quantum object that can repeatedly experience optical laser excitation and spontaneous decay, while being well isolated from its environment
The computation of potential energy surfaces (PES) is crucial for defining the landscape in which the nuclei transverse upon interacting with one another
We begin by describing our calculation of the ground and excited PESs of strontium monohydroxide SrOH

Summary

Introduction

An optical cycling center (OCC) is a recently coined term to indicate two electronic states within a complex quantum object that can repeatedly experience optical laser excitation and spontaneous decay, while being well isolated from its environment. A diverse list of promising applications for ultracold polyatomic molecules exists This includes creating novel types of sensors, advancing quantum information science, simulation of complex exotic materials, performing precision spectroscopy to test the Standard Model of particle physics, and, excitingly, the promise of control of quantum chemical reactions when each molecule is prepared in a unique rovibrational quantum state. When a ground-state alkaline-earth atom is bound to OH one of its two outer-most ns[2] electrons is transferred to the ligand, leaving the second electron in an open shell molecular orbital localized around the metal atom This electron can be optically excited without disturbing the atom-ligand bond leading to so-called highly diagonal FCFs and efficient optical cycling. Reference[12] showed that the remaining valence electron of the metal atom can be promoted to any excited orbital

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