In 2015, Campbell et al. (Nature 523, 322) presented spectroscopic laboratory gas phase data for the fullerene cation, C + 60 , that coincide with reported astronomical spectra of two diffuse interstellar band (DIB) features at 9633 and 9578 Å. In the following year additional laboratory spectra were linked to three other and weaker DIBs at 9428, 9366, and 9349 Å. The laboratory data were obtained using wavelength-dependent photodissociation spectroscopy of small (up to three) He-tagged C + 60´H e n ion complexes, yielding rest wavelengths for the bare C

We report cosmic ray ionization rates toward ten reddened stars studied within the framework of the EDIBLES (ESO Diffuse Interstellar Bands Large Exploration Survey) program, using the VLT-UVES. For each sightline, between two and ten individual rotational lines of OH + have been detected in its (0,0) and (1,0) A 3 Π − X 3 Σ − electronic band system. This allows constraining of OH + column densities toward different objects. Results are also presented for 28 additional sightlines for which only one or rather weak signals are found. An analysis of these data makes it possible to derive the primary cosmic ray ionization rate ζ p in the targeted diffuse interstellar clouds. For the ten selected targets, we obtain a range of values for ζ p equal to (3.9-16.4) × 10 −16 s −1 . These values are higher than the numbers derived in previous detections of interstellar OH + in the far-infrared/submillimeter-wave regions and in other near-ultraviolet studies. This difference is a result of using new OH + oscillator strength values and a more complete picture of all relevant OH + formation and destruction routes (including the effect of proton recombinations on PAHs), and the relatively high N(OH + ) seen toward those ten targets.

a b s t r a c tThe rotationally resolved spectrum of the B 2 P-X 2 P electronic origin band transition of 13 C 6 H is presented. The spectrum is recorded using cavity ring-down spectroscopy in combination with supersonic plasma jets by discharging a 13 C 2 H 2 /He/Ar gas mixture. A detailed analysis of more than a hundred fully-resolved transitions allows for an accurate determination of the spectroscopic parameters for both the ground and electronically excited state of 13 C 6 H.

We demonstrate that the time profile of the light intensity from domestic lighting sources exhibits simple yet interesting properties that foster lively student discussions. We monitor the light intensity of an industrial fluorescent lamp (also known as TL) and an incandescent bulb using a photodetector connected to an oscilloscope. The light intensity of these sources displays modulation at twice the ac power supply frequency. The familiarity of ac line power supply, commonplace light sources, and simplicity of the setup encourage student confidence, allowing them to think deeper and continually reassess their notions, and if managed can lead to a satisfactory explanation of the observations.