Disambiguation: Rhonda Pineda, Post-Crisis Earth-3
First published in: 2012
Rhonda Pineda first apppeared as The Atom in DC Comics - The New 52 FCBD Special Edition (DC, 2012 series) #1 (June 2012). She first appeared as the New 52 Atomica in Justice League (DC, 2011 series) #23 (October 2013). Atomica was killed in Forever Evil (DC, 2013 series) #7 (July 2014).
Reality changed at the conclusion of the Doomsday Clock event in 2020. Atomica never appeared in any story in the DC Rebirth era, and it is unknown if she existed in that continuity.
Atomica's history was altered once again following the events of Dark Nights: Death Metal (DC, 2020 series) #7 (March 2021). The Infinite Frontier Atomica was first seen in a stasis tube in Future State: Suicide Squad (DC, 2021 series) #1 (March 2021), which takes place in a possible future. She then formally debuted in Crime Syndicate (DC, 2021 series) #1 (May 2021).
Link: https://en.wikipedia.org/wiki/Atom_(character)#Rhonda_Pi%C3%B1eda/Atomica