Energy levels and transition frequencies were taken from CDMS, version of September 2005. Einstein coefficients were obtained from data presented by Sears et al (1984) and Polehampton et al. (2005). The CH₂-H₂ rate coefficients were scaled from CH₂-He rate coefficients computed by Dagdigian & Lique (2018). Collision data are presented for temperatures from 10 to 300 K.