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Picosecond transient absorption spectroscopy and transient dichroism measurements were applied for the direct elucidation of photoinduced electron-transfer dynamics (charge separation, charge recombination, and hole-transfer reactions) in poly(N-vinylcarbazole) (PVCz)−electron acceptors as well as the corresponding monomer model system N-ethylcarbazole−electron acceptors in 1,2-dichloroethane solution. The measurement of the dichroism of the ion-pair absorption in the monomer model system demonstrated that the time constants of the rotational relaxation of the anion and the cation were identical with each other, indicating that the mutual geometry of the ions in the pair was maintained at least during the rotational relaxation process. In the polymer systems, the decay of the dichroism signal of the cation was much faster than that of the anion, indicating that the rapid hole-migration process diminished the dichroism signal of the cation of the carbazolyl (Cz) groups in the PVCz chain. The electron-transfer dynamics in PVCz in 1,2-dichloroethane solution was well-described by the simple scheme that the cation continuously migrates along pendant Cz moieties in a PVCz chain with the charge recombination at the initial position of the charge separation. The time constant for the hole transfer from the cation state of Cz moiety (Cz+) to neighboring Cz's was obtained to be ca. 500 ps, although the activation energy for the hole-transfer reaction from Cz+ in the initial ion pair (which was produced by the excitation of the ground state charge transfer complex) to the neighboring Cz's was estimated to be ≫10k B T by the usual theories of electron transfer. By integrating the present results with those in other solutions and in other aromatic vinyl polymers, the factors regulating the rapid hole-transfer process in PVCz were discussed.

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Picosecond and nanosecond transient absorption spectroscopy and picosecond transient dichroism measurements were applied for elucidating photoinduced charge-separation, charge-recombination (CR), and hole-transfer (HT) processes in amorphous solid films of carbazolyl dimeric compounds (1,3-di(N-carbazolyl)propane and 1,2-trans-di(N-carbazolyl)cyclobutane) doped with 1,2,4,5-tetracyanobenzene (TCNB). Time-resolved fluorescence spectra were also measured for elucidating fluorescent states responsible for recombination emission. These results were compared with those for poly(N-vinylcarbazole) (PVCz), where the concentration of carbazolyl (Cz) chromophores is the same as the above dimeric compounds. The ground-state chargetransfer (CT) absorption and the steady-state CT fluorescence spectra were different between the present dimeric and the PVCz films. In both the films, the CR process was in competition with the HT process in the initial charge-separated state produced via the photoexcitation of the ground-state CT complex. The time constants of these processes in the amorphous dimeric compounds films were close to the values obtained for the PVCz ones. The holes (Cz + ) that escaped from the initial CR process and the immobile TCNB anion disappeared via the CR process with a t -0.5 time dependence. The CR process was interpreted as the hole diffusion-controlled geminate recombination process, as is the same as that of PVCz films. The behavior of time-resolved fluorescence attributable to the geminate CR process was different between the amorphous dimeric compounds and the PVCz films. These differences and similarities between the amorphous dimeric compounds and the PVCz films were discussed.

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Picosecond transient absorption spectroscopy and transient dichroism measurements were applied to the direct elucidation of photoinduced electron-transfer dynamics (charge separation, charge recombination, and hole-transfer reactions) in poly(5-vinylbenzo[b]carbazole) (P5VBCz) and poly(7-vinylbenzo[c]carbazole) (P7VBCz) as well as the corresponding monomer model systems in 1,2-dichloroethane solution. Electron-transfer dynamics in these polymers was well described by the simple scheme that the cation state of the benzocarbazolyl (BCz+) moiety continuously migrates along the pendent BCz moieties in the polymer chain with the charge recombination at the initial position of the charge separation. The rate constants for the hole transfer from the BCz+ to neighboring ones were found to be (180 ps)-1 for P5VBCz and (320 ps)-1 for P7VBCz. These rate constants are several orders of magnitude larger than those estimated by the standard theories of electron transfer assuming a very weak interaction between the reactants. By integrating the present results with those in other aromatic vinyl polymers, the factors regulating the rapid hole-transfer process in aromatic vinyl polymers were discussed.

Interest in atmospheric aerosol issues has been increasing worldwide. X-ray fluorescence (XRF) is an important atmospheric aerosol monitoring tool for inorganic component analysis, because XRF is a rapid and easy analysis method. In particular, Energy dispersive X-ray fluorescence (EDXRF) has drawn attention for aerosol analysis. However, EDXRF has difficulties that: (1) many overlapping peaks exist for aerosol filter analysis and (2) many thin-film standard samples are required when an empirical calibration method is employed. Accurate analysis method of aerosol filter samples without the need for large sets of standards by semi-quantitative analysis software RPF-SQX (Rigaku profile fitting-spectra quant X), which includes the exact profile fitting and thin-film fundamental parameter (FP) method, is described using the EDXRF spectrometer equipped with secondary targets and polarized optics.

X-ray fluorescence spectrometry using the 'standardless' fundamental parameter method has been studied for the whole elemental analysis of magnesium alloys. Twelve major elements were determined: Mg, Al, Si, Ca, Mn, Fe, Ni, Cu, Zn, Ag, Sn and Pb. Specimens used were over 30 mm in diameter and greater than 10 mm thick to determine Sn K which has the largest analyzing depth (9 mm) through the alloy samples. Surfaces of the specimens were polished with fine alumina abrasive paper (# 240) to remove the oxide layer and to avoid the influence of surface roughness variation on the intensities of Mg K, Al K and Si K which have smaller analyzing depths. The total quantitative values of the 12 elements determined by the FP calculation were normalized to 100 mass%. The analytical values obtained by this method were comparable to those obtained by the conventional calibration curves method. The relative standard deviations were 6.6 % for 0.0014 mass% of Ni, and 0.005 % for 93.82 mass% of Mg in AZ91 series Mg alloys. Validation results of the proposed method for 12 elements were successful for the five CRMs tested.