Comparison of desorption profiles generated with the TST (red) or the Hasegawa (blue) prefactor. Left panel: Desorption profiles of CH₃NCO, CH₃C(O)NH₂, and NH₂C(O)NH₂. The desorption energies are determined with the Redhead-TST method using data from Ligterink et al. (2017, 2018a; see Table A.2 and top left corners). Desorption profiles are plotted for v_TST (red) and with v_Hasegawa (blue). The desorption profile is simulated with a first-order Polanyi-Wigner equation, surface coverage of 1 × 10¹⁵ molecules cm⁻², and heating rate of 1 K century⁻¹. Peak desorption temperatures decrease by ~30% when realistic pre-factors are used. Right panel: Ice (solid) and gas (dashed) abundances plotted against radius (au) of a protoplanetary disk for v_TST (red) and with v_Hasegawa (blue). An average disk temperature profile of T(r) = 200 × (r/1 AU)^0.62 K is used (Andrews & Williams 2007). For each 1 K temperature step, the number of desorbed molecules is determined, which summed give the gas-phase column density and subtracted from a starting value of 1 × 10¹⁵ cm⁻² give the ice column density. The TST abundances are offset by a factor of 10 for easier viewing. The peak radii of the ice-gas inversion are indicated and are shown to shift outward by ~50% when realistic pre-factors are used.