Fluorescence excitation spectra of 4-(diisopropylamino)benzonitrile (DIABN) and 4-(dimethylamino)benzonitrile (DMABN) in thermal vapour and seeded jet expansions are compared. The spectrum of jet-cooled DIABN shows an intense 0±0-transition at 31751:8 cm À1 . The spectrum collapses at excess excitation energies above 800 cm À1 , indicating the presence of an ecient non-radiative decay channel. In the gas phase,¯uorescence emission of DIABN occurs from the intramolecular charge transfer (ICT) state. The non-radiative decay channel, therefore, is attributed to rapid ICT in the isolated molecule. The related compounds 4-(methylamino)-3,5-dimethylbenzonitrile (MHD), 4-(azetidinyl)-3,5dimethylbenzonitrile (M4D), and 4-(dimethylamino)-3,5-dimethylbenzonitrile (MMD) in the jet show extremely weak and structureless emission.

Abstract. This work provides a first experimental measurement of broadened ECH deposition on the DIII-D tokamak. As seen in theory[1] and simulation [2], refraction by edge density fluctuations shifts the path of RF waves, altering ECH and ECCD deposition. This paper reports on an initial experimental confirmation of broadened ECH deposition on DIII-D tokamak. T e measurements from a 48 channel 2nd Harmonic ECE Radiometer digitized at 500 kHz are used with a set of broadened trial ECH deposition functions to calculate time-dependent, modulation-induced heat fluxes. The fitting of convective and diffusive transport to these fluxes allows different ECH deposition profiles to be compared. The best-fit ECH deposition produces reasonable transport coefficients which compare favorably with simulation. This method is applied to a set of L-and H-mode DIII-D discharges. Accounting for diffusive, convective, and coupled transport, the ECH deposition profile is found to be 2 to 3 times wider than predicted by TORAY-GA ray tracing.

Fluorescence Excitation Spectra / 1,1 -bi(benzocyclobutylidene) / PhotoisomerizationFirst measurements of fluorescence excitation spectra of the recently synthesized rigid stilbene analogue 1,1 -bi(benzocyclobutylidene) in a supersonic jet expansion show that, in contrast to the parent compound, both the trans-and the cis-conformer fluoresce under these conditions. The excitation energy dependence of fluorescence lifetimes indicates the onset of an efficient non-radiative decay channel above energy thresholds of 1340 cm −1 and 990 cm −1 for the trans-and cis-form, respectively, which is assigned to photoisomerization in the singlet state. From an RRKM analysis of the microcanonical rate coefficients an estimate of the high pressure limit of the thermal photoisomerization rate coefficient is obtained and compared with photoisomerization rate coefficients measured in low viscosity solution and in thermal vapor. There are strong indications that for this compound there are no dynamic or static solvent induced effects that lead to an anomalous acceleration of the reaction in solution.

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