title: Prospects for ultracold carbon via charge exchange reactions and laser cooled carbides.
abstract: Strategies to produce an ultracold sample of carbon atoms are explored and assessed with the help of quantum chemistry. After a brief discussion of the experimental difficulties using conventional methods, two strategies are investigated. The first attempts to exploit charge exchange reactions between ultracold metal atoms and sympathetically cooled C(+) ions. Ab initio calculations including electron correlation have been conducted on the molecular ions [LiC](+) and [BeC](+) to determine whether alkali or alkaline earth metals are a suitable buffer gas for the formation of C atoms but strong spontaneous radiative charge exchange ensure they are not ideal. The second technique involves the stimulated production of ultracold C atoms from a gas of laser cooled carbides. Calculations on LiC suggest that the alkali carbides are not suitable but the CH radical is a possible laser cooling candidate thanks to very favourable Frank-Condon factors. A scheme based on a four pulse STIRAP excitation pathway to a Feshbach resonance is outlined for the production of atomic fragments with near zero centre of mass velocity.
authors.affiliation: Innovative Molecular Materials Group, School of Chemistry and Chemical Engineering, Queen's University of Belfast, Stranmillis Road, Belfast, UK BT9 5AG.
authors.forename: Nathan
authors.initials: N
authors.lastname: Wells
authors.forename: Ian C
authors.initials: IC
authors.lastname: Lane