Energetics of the reaction. The calculated barrier height is including zero-point energy corrections. The shaded curve is the collisional energy distribution of at a translational temperature of with its maximum at and FWHM of . The vibrational excitation laser excites into one of the three vibrational eigenstates, and , near . Laser pulses probe the products by REMPI through the , , , or resonant transitions. We also include the vibrational levels of the reactant and the product species, however, the shaded levels are unobserved in this work.
(a) Photoacoustic absorption spectrum of at . The intensity below is scaled by a factor of 2 to emphasize the rotational structure. The dashed vertical lines are the transitions that have primarily C–H stretch character calculated by CVPT. (b) Action spectrum of the reaction monitoring the transition. The arrows show the positions of four observed transitions at 5766, 5782, 5841, and . (c) Action spectrum of the reaction monitoring the transition. The solid arrows in (b) and (c) mark the transitions used to record the product state distributions. There is no appreciable signal below , nor is there signal above .
(a) Experimental and simulated action spectra of . The simulation calculates the individual symmetry species separately and normalizes the -symmetry component to the transition of the action spectrum. The -symmetry component is scaled and summed with the -symmetry component to reproduce the observed action spectrum. (b) Experimental room-temperature photoacoustic and simulated absorption spectra of . The simulation procedure is the same as for the action spectrum.
Mass-resolved REMPI product state distributions for initial excitation of (a) the , (b) the , and (c) the states. (d) Mass-resolved REMPI product state distribution of the thermal reaction, . The light vertical lines mark the and transitions in the REMPI of . We simultaneously record the and signals for each reaction.
Mass-resolved REMPI spectra of the products for the reactions of (this work) and (Ref. 34).
Fundamental normal modes (fundamental frequencies taken from Ref. 20) and C–H stretch overtone and combination transitions of . Also included are the correlations between normal modes and local modes.
The calculated normal mode frequencies for and . Calculations are at the MP2 level of theory with a basis set and the results are scaled by the recommended factor of 0.9434. All frequencies are in units of .
Article metrics loading...
Full text loading...