Fig. 5: Confirming the chemical formulae.

TPD profiles measured at 11.26 eV with isotopically substituted ices for A the dissociative photoionization product (CH(OH)2+) of methanetriol (CH(OH)3), B carbonic acid (HOCOOH), and C the dissociative photoionization product (C(OH)3+) of methanetetrol (C(OH)4).