The four known molecular absorption line systems at redshifts z=0.25–0.89 are discussed. Two of the systems originate in the galaxy hosting the ‘background’ AGN, while in two cases the absorption occurs in truely intervening galaxies. Indirect evidence for the existence of very small scale structure in the molecular ISM is presented. A new absorption line at z=0.89 towards PKS1830–211 opens up ...

Context. Studying the composition of dust in the interstellar medium (ISM) is crucial for understanding the cycle of dust in our galaxy. Aims. The mid-infrared spectral signature of amorphous silicates, the most abundant dust species in the ISM, is studied in different lines-of-sight through the Galactic plane, thus probing different conditions in the ISM. Methods. We have analysed ten spectra ...

This paper demonstrates the use of acoustic absorption measurements to characterize the level of molecular mixing between gaseous mixtures. This objective is motivated by the observation that many existing methods only quantify macro-scale entrainment. Over a large range of frequencies, acoustic damping is dominated by vibrational relaxation processes. Our approach takes advantage of the fact t...

The electronic absorption and emission spectra of large molecules reflect the extent and timescale of electron-vibration coupling and therefore the extent and timescale of relaxation/reorganization in response to a perturbation. In this paper, we present a comparison of the calculated absorption and emission spectra of NADH in liver alcohol dehydrogenase (LADH), using quantum mechanical/molecul...

The UV-Vis absorption spectrum and LIF emission spectrum of I2 were found for the purpose of gaining information about the energy of the ground X( 1 Σg + ) and excited B( 3 Π0u + ) states. This information was compared to information obtained from the Gaussian program which uses quantum mechanical calculations and numerical approximations to predict electronic energy levels. The iodine molecule...

A high-finesse optical cavity was employed to perform highly sensitive spectroscopy of molecular oxygen at wavelengths near 763 nm. An equivalent absorption length of ;1 km was obtained by a 26-cm-long optical cavity with a finesse of 6000. An extended cavity diode laser was frequency locked to the cavity, and pure absorption profiles were recovered by monitoring of the cavity transmission duri...