Time of flight mass spectra showing relative yields of parent and fragment ( and ) ions following one color excitation of jet-cooled molecules at (lower trace) and upon introduction of a second laser pulse, delayed by , at (upper trace). For clarity, the weaker features in the lower trace are also displayed on a expanded vertical scale.
fragment ion speed distributions resulting from photolysis of cations at (a) , (b) , and (c) . The assignment comb in panel (a) indicates the fragment ion speeds predicted, by energy conservation, for different states of the partner product.
Raw images and speed distributions of the fragments resulting from (a) photolysis at and (b) photolysis at . Peaks attributable to one photon dissociation to fragments are indicated. The assignment combs indicate the expected speeds of two photon produced fragment ions formed with cofragments in different vibrational states.
Detail of the TOF mass spectra obtained following (a) photolysis at the four indicated wavelengths in the range , and (b) photolysis at three wavelengths in the range , illustrating the way in which the width of the 32 peak varies with isotopic substitution and with . The weak feature at 33 in (b) is attributable to fragment ions from trace and/or HDS impurity in the sample.
Images recorded by setting the intensifier time gate (duration ) at different times within the 32 peak in the TOF spectrum recorded following photolysis at . The chosen time windows are (a) , (b) , (c) , and (d) , where defines the time when the ions are first detected.
Raw image and speed distribution of the fragments resulting from excitation of at . The lower panel shows the derived speed dependence of the anisotropy parameter ; a trend line is positioned through the data to guide the eye.
Speed distributions of 33 fragment ions from photolysis at , , and . The vertical lines indicate the maximum speed of fragments allowed, by energy conservation, from the one photon dissociation of parent ions [process (2)] at these three excitation wavenumbers.
Speed distributions of 33 fragment ions from photolysis at , (b) , and (c) . The superimposed combs indicate the product speeds expected for different electronic and vibrational states of the fragment ion assuming that dissociation is brought about by absorbing two photolysis laser photons.
Speed distributions of 33 fragment ions from photolysis at , (b) , and (c) . The superimposed combs indicate the maximum product speeds expected for two photon dissociations yielding products in the level of their , , and states.
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