barrierless

Adjective

barrierless (not comparable)

1. Lacking barriers
   • The world is increasingly barrierless.
   • High Mill crossing, at present gated and manually-operated, will become a barrierless rural-type crossing.1979 August, Michael Harris, “A line for all reasons: the North Yorkshire Moors Railway”, in Railway World, page 412
2. (physical) Not requiring activation energy.
   • The reaction is then barrierless, ie, ΔG* = 0, and the rate constant is a maximum for the given λ (Figure 6).1992, R.A. Marcus, Prabha Siddarth, “Theory of Electron Transfer Reactions and Comparison with Experiments”, in Elise Kochanski, editor, Photoprocesses in Transition Metal Complexes, Biosystems, and...