Fig. 4. IR spectra of two conformers of Galβ(1-4)GlcNAc acquired with the IR–IR double resonance method (downward pointing) with the pump laser fixed at 3536 cm–1 (red) and at 3498 cm–1 (blue), respectively. The spectra of the ion-mobility separated species 1 and 2 (upward pointing) are displayed for comparison in red and blue, respectively.
