Imaging molecular dynamics

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Interactive Raman spectra of adamantane, diamantane and diamond, and their relevance to diamond film deposition

Laser Raman spectra have been obtained for crystalline adamantane, diamantane, and natural type II diamond, as well as for a diamond film grown by chemical vapour deposition (CVD). The spectra are presented in JCAMP format to allow on-line interaction with the data by the reader, and 3D structure animations are presented showing the most probable vibrational mode causing each peak in the various spectra. The spectra are compared to those often seen from CVD diamond films, and which contain peaks that have previously been assigned to 'nanophase' diamond. Although there is a superficial correlation between the peak positions for the polymantanes and those seen in CVD diamond, the conclusion is that the nanophase diamond peaks are not an intrinsic vibrational mode of a polymantane, but instead must be a result of some other aspect of the nanophase scale of the films, such as surface modes

Two-photon resonance enhanced MPI-PES above the lowest ionization threshold: observation of the [a E1delta]5p pi E2phi state of the SH (SD) radical

A (2 + 1) resonance enhanced multiphoton ionization photoelectron spectroscopy (REMPI-PES) study of the hitherto unobserved [a 1D]5p 2 Rydberg state of the SH (SD) radical is reported. Despite the fact that this state has an excitation energy which exceeds the lowest ionization energy, ionization is observed to occur preferentially by the absorption of a third photon after the two-photon excitation step, rather than through autoionization. Photoelectron spectra show a large asymmetry in the rotational branching ratios, which is attributed to the high value of + in the ionic state

Imaging the dynamics of gas phase reactions

Contains fulltext : 35734.pdf (publisher's version ) (Open Access)Ion imaging methods are making ever greater impact on studies of gas phase molecular reaction dynamics. This article traces the evolution of the technique, highlights some of the more important breakthroughs with regards to improving image resolution and in image processing and analysis methods, and then proceeds to illustrate some of the many applications to which the technique is now being applied-most notably in studies of molecular photodissociation and of bimolecular reaction dynamics

High-resolution ion-imaging studies of the photodissociation of the BrCl⁺ Cation

The photofragmentation of state-selected BrCl+ cations has been investigated by velocity-map ion-imaging methods. Detailed analyses of the 79Br+ fragment velocities lead to the most precise values yet reported for (i) the spin-orbit coupling constant for the X2 state, A = -2070 ± 4 cm-1; (ii) the bond dissociation energies of both states of 79Br35Cl+, 25019 ± 4 cm-1 (X23/2) and 22949 ± 2 cm-1 (X21/2); and (iii) the adiabatic ionization thresholds for forming 79Br35Cl+ parent ions in their X23/2 and X21/2 states, 88292 ± 6 and 90362 ± 4 cm-1, respectively