Starting with ultracold #123;87#125;Rb atoms, we apply pulses of frequency-chirped light to first photoassociate the atoms into excited molecules and then, later in the chirp, de-excite these molecules into a high vibrational level of the lowest triplet state, a#92;,#123;3#125;#92;Sigma#95;#123;u#125;#123;#43;#125;.
Source: wiktionary