Schematic representation of the velocity-mapped ion imaging instrument used in these experiments. The dissociation (d), probe (p), and ionization (i) laser pulses interact with the sample at right angles to both the skimmed molecular beam and the time-of-flight axis.
ion images from the 305 nm photodissociation of PhNO from the (33.5) transition. Images (a)–(d) are the raw images from varying the linear polarization of the dissociation and probe lasers from parallel to perpendicular to the detector plane. Blue is the most intense part of the ion image and black indicates no ions were detected. Images (e) and (f) are the differences between images when the polarization of the probe beam is held constant and the dissociation beam is changed. Images (g) and (h) are difference images when the polarization of the dissociation laser is held constant and the probe laser polarization is changed. Blue indicates a positive difference between the images. Red indicates a negative difference.
Synthetic ion images based on forward convolution fits to the bipolar moments and velocity distributions determined for the data in Fig. 2. The simulated ion images (a)–(d) show the most intense portion of the distribution in blue and the lowest in black. The orientation of the plane-polarized dissociation and probe beams are as indicated. The difference images (e) and (f) show the effect of changing the polarization of the dissociation beams. The difference images (g) and (h) show the differences of changing the probe polarization as the dissociation pulse is held constant. Positive differences in images (e)–(h) are blue. Negative differences are red.
The two lambda doublet states for each NO rotational level: the (symmetric) state with the electron in the plane of rotation or the (antisymmetric) state with the unpaired electron in the orbital out of the plane of rotation.
Depiction of the highest occupied molecular orbitals for the parent and asymptotic products from the dissociation of PhNO on its (a) state potential energy surface and (b) potential energy surface.
Necessary trajectories to produce NO in the state with from the and states. In (a) dissociation from , the simple scission of the C–N bond, puts the lone electron in the state if the NO exits in a propellerlike trajectory; (b) shows the unlikely method of generating NO in the state, requiring that NO dissociate along a path perpendicular to the phenyl ring.
Time-dependent DFT calculated vertical excitation energies for , , and , at a number of dihedral angles. The energy of , also shown, changes as the dihedral angle changes, showing the calculated barrier to internal rotation in the ground state.
Optimized values, indicating the vector correlation between velocity and angular momentum , for selected rovibronic transitions in NO following the 305 nm photodissociation of PhNO. Also reported are the average speed, , of the anisotropic component and the average speed, , of the isotropic component for each transition.
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