# Searching for stable fullerenes in space with computational chemistry

## TL;DR

This study uses computational chemistry to analyze the stability and infrared spectra of various fullerene cages, aiming to identify potential fullerene species in space beyond C60 and C70.

## Contribution

It introduces a computational approach to predict stability and IR spectra of fullerene cages with 44-70 carbon atoms, suggesting smaller cages may exist in space.

## Key findings

- Simulated IR spectra match observed spectra of some planetary nebulae.
- Smaller fullerene cages (44, 50, 56 atoms) may be present in space.
- C60 and C70 are the most confidently identified fullerenes in space.

## Abstract

We report a computational study of the stability and infrared (IR) vibrational spectra of neutral and singly ionised fullerene cages containing between 44 and 70 carbon atoms. The stability is characterised in terms of the standard enthalpy of formation per CC bond, the HOMO-LUMO gap, and the energy required to eliminate a C$_2$ fragment. We compare the simulated IR spectra of these fullerene species to the observed emission spectra of several planetary nebulae (Tc 1, SMP SMC 16, and SMP LMC 56) where strong C$_{60}$ emission has been detected. Although we could not conclusively identify fullerenes other than C$_{60}$ and C$_{70}$, our results point to the possible presence of smaller (44, 50, and 56-atom) cages in those astronomical objects. Observational confirmation of our prediction should become possible when the James Webb Space Telescope comes online.