Matrix isolation FTIR studies of non-planar trans-stilbene

► For the first time, trapped the non-planar trans-stilbene in inert gas matrixes. ► Non-planar structure obtained by photo-irradiating cis-stilbene in ∼10K matrixes. ► Detailed infrared spectra recorded for the non-planar stilbene. ► Earlier studies in gas phase and crystals yielded non-planar or planar trans form. ► Our matrix isolation experiments yielded both forms of the trans-stilbene.