Fig. 2: Rotational structures of N2O aligned by two laser kicks.
From: Observing collisions beyond the secular approximation limit
a Alignment signal recorded in pure N2O gas at low pressure by scanning the temporal delay between the first aligning pulse P1 (at t = 0) and the probe pulse over slightly more than the full rotational period TR = 40.4 ps of the molecule. The peaks identified by P1 and P2 correspond to the transient alignment signals produced by the two pulses separated by the delay τ12. The main echo is generated at t = 2τ12, with the secondary echo observable at t = 3τ12, and the imaginary echo produced at TR/2-τ12 (equivalent features also appearing at times shifted by +TR/2). In addition to echoes, other transients corresponding to the standard half and full alignment revivals of P1 (at TR/2 and TR) and P2 (at TR/2 + τ12 and TR + τ12) are also observed. b Alignment traces of N2O diluted in He measured at various densities around the main echo at 2τ12 for τ12 = 2.18 ps. The amplitudes S of the alignment structures are measured from peak to dip. c Amplitudes of the half revival (open red circles), full revival (full blue circles), and of the main echo for five different values of the delay τ12 versus the gas density d multiplied by the time of observation tR (TR/2 or TR) and 2τ12 for the revivals and echo, respectively, expressed in picosecond amagat (ps.amagat, with 1 amagat = 2.687 × 1025 mol. m−3) units. The lines indicate the best exponential fits.
