We investigate the consistency of the labeling and assignments of the vibrations of the monosubstituted benzenes in the electronic ground state. In doing so, we also identify some inconsistencies in the labeling of the benzene modes. We commence by investigating the behavior of the benzene vibrations as one hydrogen is replaced by an artificial atomic substituent of increasing mass via quantum chemical calculations; the wavenumber variations with mass give insight into the assignments. We also examine how well the monohalobenzene vibrations can be described in terms of the benzene ones: consistent with some recent studies, we conclude that this is futile in a significant number of cases. We then show that "isotopic wavenumbers" obtained by artificially changing the mass of the fluorine atom in fluorobenzene are in very good agreement with the wavenumbers obtained via explicit calculation for the relevant monohalobenzene (chlorobenzene, bromobenzene, and iodobenzene) vibrations. As a consequence, we propose that the vibrations of monofluorobenzene be used as the basis for labelling the vibrational assignments of monosubstituted benzenes. As well as the four monohalobenzenes, we also apply this approach to the vibrations of aniline, toluene, benzonitrile, phenylacetylene, phenylphosphine, and nitrobenzene. This has allowed a much more consistent picture of the vibrational assignments to be obtained across ten monosubstituted benzenes.

We investigate the low-energy transitions (0-570 cm -1 ) of the S1 state of para-fluorotoluene (pFT) using a combination of resonance-enhanced multiphoton ionization (REMPI) and zerokinetic-energy (ZEKE) spectroscopy and quantum chemical calculations. By using various S1states as intermediate levels, we obtain zero-kinetic-energy (ZEKE) spectra. The differing activity observed allows detailed assignments to be made of both the cation and S1 lowenergy levels. The assignments are in line with the recently-published work on toluene from the Lawrance group [J. Chem. Phys. 143, 044313 (2015)], which considered vibration-torsion coupling in depth for the S1 state of toluene. In addition, we investigate whether two bands that occur in the range 390-420 cm -1 are the result of a Fermi resonance; we present evidence for weak coupling between various vibrations and torsions that contribute to this region. This work has led to the identification of a number of misassignments in the literature, and these are corrected.2

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High-level ab initio calculations are performed on the coinage metal cations ͑Cu + , Ag + , and Au + ͒ interacting with each of the rare gases ͓Rg ͑Rg=He to Rn͔͒. The RCCSD͑T͒ procedure is employed, with basis sets being of approximately quintuple-quality, but with the heavier species using relativistic effective core potentials. The interaction potentials are compared to experimental and theoretical data where they exist. In addition, transport coefficients for the mobility and diffusion of the cations in the rare gases are calculated. The latter have involved a rewriting of some of the programs used, and the required modifications are discussed. The mobility results indicate that, rather than being a rare occurrence, mobility minima may be common phenomena. Finally, a new estimate is put forward for the validity of zero-field mobilities in ion mobility spectrometry.

We present high level ab initio potential energy curves for the M(n+)-RG complexes, where n = 1, 2, RG = rare gas, and M = Be and Mg. Spectroscopic constants have been derived from these potentials, and they generally show very good agreement with the available experimental data. The potentials have also been employed in calculating transport coefficients for M(+) moving through a bath of RG atoms, and the isotopic scaling relationship is examined for Mg(+) in Ne. Trends in binding energies, D(e), and bond lengths, R(e), are discussed and compared to similar ab initio results involving the corresponding complexes of the heavier alkaline earth metal ions. We identify some very unusual behavior, particularly for Be(+)-Ne, and offer possible explanations.

Specific interactions between proteins and their binding partners are fundamental to life processes. The ability to detect protein complexes, and map their sites of binding, is crucial to understanding basic biology at the molecular level. Methods that employ sensitive analytical techniques such as mass spectrometry have the potential to provide valuable insights with very little material and on short time scales. Here we present a differential protein footprinting technique employing an efficient photo-activated probe for use with mass spectrometry. Using this methodology the location of a carbohydrate substrate was accurately mapped to the binding cleft of lysozyme, and in a more complex example, the interactions between a 100 kDa, multi-domain deubiquitinating enzyme, USP5 and a diubiquitin substrate were located to different functional domains. The much improved properties of this probe make carbene footprinting a viable method for rapid and accurate identification of protein binding sites utilizing benign, near-UV photoactivation.

A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk *To whom correspondence should be addressed. Email: Tim.Wright@nottingham.ac.uk AbstractWe give a description of the phenyl-ring-localized vibrational modes of the ground states of the paradisubstituted benzene molecules including both symmetric and asymmetric cases. In line with others,we quickly conclude that the use of Wilson mode labels is misleading and ambiguous; we conclude the same regarding the related ones of Varsányi. Instead we label the modes consistently based upon the Mulliken (Herzberg) method for the modes of para-difluorobenzene (pDFB). Since we wish the labelling scheme to cover both symmetrically-and asymmetrically-substituted molecules, we apply the Mulliken labelling under C 2v symmetry. By studying the variation of the vibrational wavenumbers with mass of the substituent, we are able to identify the corresponding modes across a wide range of molecules and hence provide consistent assignments. Particularly interesting are pairs of vibrations that evolve from in-and out-of-phase motions in pDFB to more localized modes in asymmetric molecules. We consider the para isomers of the following: the symmetric dihalobenzenes, xylene, hydroquinone, the asymmetric dihalobenzenes, halotoluenes, halophenols and cresol.Keywords: Frequencies; Ground state; Substituted benzenes. 2 I. INTRODUCTIONBecause an understanding of the trends in the vibrational spectroscopy and dynamics of molecules is linked to being able to refer to the same vibrational motions (normal modes) across species, it is desirable to label these in as consistent a manner as possible. In this way, when referring to a labelled vibration in one molecule, one can be sure of talking about the same vibration in a different molecule.Since there are a whole range of substituted benzenes, it has been very common to refer to the phenylring-localized vibrations of any such molecule in terms of the vibrations of the parent benzene molecule via the Wilson labelling scheme [1]. In previous work on the monosubstituted benzenes it has been noted by our group [2] and others [3,4] that in fact the use of the Wilson labelling scheme is fraught with uncertainty owing to the large differences between the forms of the normal modes of benzene and those of the monosubstituted species; this difference occurs even for the substitution of H for D in monodeuterated benzene [2]. This has been recognized by many workers, perhaps most notably Varsányi [5], who attempted to bring consistency to the labelling by proposing Wilson-type labels for a whole range of substituted benzenes; unfortunately, however, this was hampered by incomplete data sets, and there was also inconsistency conce...

We present the results of an ab initio study of the interaction of electronically excited NO(A (2)Sigma(+)) with rare gas (Rg) atoms. The bound states of each NO(A)-Rg species are determined from potential energy surfaces calculated at the RCCSD(T) level of theory. Making use of the NO(X (2)Pi)-Rg vibrational wavefunctions, we then simulate electronic spectra. For NO-Kr and NO-Xe we obtain good qualitative agreement with the previously published experimental spectra. For NO-Ar, the shallowness of the surface gives rise to agreement that is less satisfactory, but a global scaling provides better qualitative agreement. The assignment of the spectra is far from straightforward and is only possible with guidance from the calculated energies and wavefunctions of the energy levels of the complex. Previous assignments are discussed in the light of this conclusion.