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New Applications of Broadband Rotational Spectroscopy

Final Report Summary - CPFTMW (New Applications of Broadband Rotational Spectroscopy)

The vision for CPFTMW-307000 was to apply the technique of broadband rotational spectroscopy to answer important, fundamental questions relevant across many areas of contemporary research. In addition, the project explored applications of broadband rotational spectroscopy in chemical analysis alongside an industrial partner.

The discoveries of CPFTMW-307000 repeatedly highlighted the value of broadband rotational spectroscopy as a powerful tool allowing the simultaneous detection of many different chemical products. Results provided insights beyond those which could be gained through the study of a single molecule or complex within the expanding gas sample. It was unexpectedly discovered that PtC3 and PdC3 are generated efficiently when the metal is vaporised in the presence of a hydrocarbon. This result provided strong evidence in support of a proposal that platinum/palladium can be regarded as the isoelectronic and isolobal counterpart of a chalcogen for the purposes of predicting structure and reactivity trends.

The strength and nature of hydrogen bonding to nitrogenous bases was an important theme of the publications yielded by CPFTMW-307000. Laser vaporisation of imidazole was found to cause the formation of HC5N, HC7N and CH3C3N within the expanding gas sample. The length of the hydrogen bond formed between two isolated imidazole molecules was determined from data obtained during this programme of experiments. It was shown that the geometry of a complex of urea and isocyanic acid is governed by a cooperative pair of hydrogen bonds. The hydrogen bonding properties of urea are of prototypical importance in biology and crystal engineering. The strengths of halogen bonds to iodopyrazole and bromopyrazole were studied with the aim of explaining how these molecules attach efficiently to protein binding sites. Data obtained for complexes containing other nitrogenous bases including methylimidazole and thiourea are currently being analysed and will be the subject of future publications.

In collaboration with an industrial partner, AWE(Aldermaston), applications of broadband rotational spectroscopy for the analysis of chemical composition in room temperature samples were explored. The results were shared with AWE, and also with researchers engaged in remote sensing of the earth’s atmosphere. Alongside the scientific findings of CPFTMW-307000, collaborators were engaged from Belgium, Germany, Spain, Canada and the UK with the aim of strengthening international networks; and increasing the reach and impact of scientific outcomes. The destinations of group members who moved onto subsequent postdoctoral research appointments were similarly diverse and included institutions in the USA, Canada, the UK and the Netherlands.