A printable hydrogen‐bonded cholesteric liquid crystal (CLC) polymer film is described, which can be used as a sensor for detection of gaseous trimethylamine (TMA). In this optical sensor the virgin CLC polymer network reflects green light. When anhydrous TMA gas penetrates the film, disruption of the hydrogen bonds occurs, with the simultaneous formation of carboxylate salts. The consequent reduction of the molecular order causes the green reflecting CLC film to become colorless. However, exposure to TMA in water‐saturated nitrogen gas results in a red reflecting film. Due to the hygroscopic nature of the polymer salt that is formed by TMA, water vapor which is present in the environment is absorbed by the films. This leads to swelling of the film, resulting in an increase in pitch size and therefore a red shift of the reflection band. Interestingly, after exposure to ambient conditions, restoration of the green reflecting film takes place, showing that the sensor can be used multiple times. In a proof of principle experiment, it was shown that these CLC films can be used as optical sensors to detect volatile amines, that are produced by decaying fish.

The dissociation energies of singly charged silver cluster cations, Agn+ (2⩽n⩽25), are determined by multiple-collision induced dissociation (MCID) in a Penning trap. The fragment yield is analyzed in terms of a linearized impulsive collision theory for the energy transfer in the multicollisional process and the delayed decay as predicted by the Rice–Ramsperger–Kassel (RRK) model. Previous photofragmentation experiments performed in the size range (9⩽n⩽21) are found to be in good agreement with the present results. Theoretical predictions agree for most clusters sizes.

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The time-resolved decay of silver clusters Ag n ϩ (nϭ8Ϫ21) has been observed after excitation by photons with energies 1.5-4 eV. Clusters were found to decay by emission of neutral atoms or dimers with lifetimes in the range 100 s to 15 ms. Separation energies were calculated from the lifetimes assuming a statistical unimolecular decay. As a function of cluster size, the resulting values increase towards the bulk cohesive energy of silver. They show a pronounced odd-even alternation and an indication of a shell closure at nϭ9. The separation energies for nϭ8,9 are in good agreement with configuration-interaction ab initio calculations.

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