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Absorption spectra toward Herschel 36 (Her 36) for the Ã1∏ ← ~X1∑ transitions of CH+ in the J = 1 excited rotational level and for the Ã2Δ ← ~X2∏ transitions of CH in the J = 3/2 excited fine structure level have been analyzed. These excited levels are above their ground levels by 40.1 K and ~25.7 K and indicate high radiative temperatures of the environment of 14.6 K and 6.7 K, respectively. The effect of the high radiative temperature is more spectacular in some diffuse interstellar bands (DIBs) observed toward Her 36; remarkable extended tails toward red (ETRs) were observed. We interpret these ETRs as being due to a small decrease of the rotational constants upon excitation of the excited electronic states. Along with radiative pumping of a great many high-J rotational levels, this causes the ETRs. In order to study this effect quantitatively, we have developed a model calculation in which the effects of collisions and radiation are treated simultaneously. The simplest case of linear molecules is considered. It has been found that the ETR is reproduced if the fraction of the variation of the rotational constant, α ≡ (B'-B)/B, is sufficiently high (3%-5%) and the radiative temperature is high (Tr > 50 K). Although modeling for general molecules is beyond the scope of this paper, the results indicate that the prototypical DIBs λ5780.5, λ5797.1, and λ6613.6 which show the pronounced ETRs are due to polar molecules that are sensitive to the radiative excitation. The requirement of high α favors relatively small molecules with three to six heavy atoms. DIBs λ5849.8, λ6196.0, and λ6379.3 that do not show the pronounced ETRs are likely due to non-polar molecules or large polar molecules with small α. [ABSTRACT FROM AUTHOR]

We present the intrinsic optical properties over a broad spectral range of TiN thin films deposited on an Si/SiO2 substrate. We analyze the measured reflectivity spectra of the film-substrate multilayer structure within a well-establish procedure based on the Fresnel equation and extract the real part of the optical conductivity of TiN. We identify the metallic contribution as well as the finite energy excitations and disentangle the spectral weight distribution among them. The absorption spectrum of TiN bears some similarities with the electrodynamic response observed in the normal state of the high-temperature superconductors. Particularly, a mid-infrared feature in the optical conductivity is quite reminiscent of a pseudogap-like excitation. [ABSTRACT FROM AUTHOR]

ZnO nanorod close-packed arrays are successfully fabricated in a substrate-free manner by a citric acid assisted annealing process at a low growth temperature of 400 °C. Each nanorod of ZnO nanorod close-packed arrays grows along the [0001] direction and is single crystalline with an average diameter of 50 nm, and an average length of 0.5 µm. The aspect ratio is 10. The ZnO nanorod close-packed arrays show a strong exciton absorption peak at 372 nm in UV-visible absorption spectra, exhibiting a blue-shift relative to the bulk exciton absorption (387 nm). Finally, a new growth mechanism is proposed for the substrate-free preparation of ZnO nanorod close-packed arrays by a citric acid assisted annealing process. [ABSTRACT FROM AUTHOR]