OBSERVATION OF SOME Ω = 1/2 ELECTRONIC STATES OF NICKEL DEUTERIDE, NiD, WITH LASER-INDUCED FLUORESCENCE

\begin{wrapfigure}{l}{0pt} \includegraphics[scale=0.16]{GraphAbs.eps} \end{wrapfigure} The five lowest-lying electronic states of nickel hydride (NiH) are usually labeled $^2\Delta_{5/2}$, $^2\Pi_{3/2}$, $^2\Delta_{3/2}$, $^2\Sigma^+_{1/2}$ and $^2\Pi_{1/2}$, although there is significant mixing between them. These states arise from the $d^9$ electron configuration of Ni$^+$, perturbed by an H$^-$ ligand. A variety of vibrational levels has been observed in each, and the aggregate data set has been well modelled as a `supermultiplet' by the Field group\footnote{J. A. Gray, M. Li, T. Nelis and R. W. Field, J. Chem. Phys. \textbf{95}, 7164 (1991)}. For the deuterated isotopologue NiD, only the $^2\Delta_{5/2}$, $^2\Pi_{3/2}$ and $^2\Delta_{3/2}$ states have been reported in the literature. A multi-isotope supermutiplet fitting including both the NiH and (more limited) NiD data\footnote{M. Abbasi, A. Shayesteh, P. Crozet and A. J. Ross, J. Mol. Spectrosc. \textbf{349}, 49 (2018)} provided predictions for the two $\Omega=1/2$ states of the NiD supermultiplet. Experimental observation was needed to validate (and improve) the model. We report on laser-induced fluorescence experiments conducted both at the University of New Brunswick and at Universit\'e Lyon 1 in which the $^2\Sigma^+_{1/2}, v=0,1,2$ and $^2\Pi_{1/2},v=0,1$ levels of NiD were identified and rotationally analyzed. The existing multi-isotope supermultiplet model proved remarkably accurate in predicting the energy and structure of these $\Omega=1/2$ states. In addition, a higher-lying $\Omega=1/2$ electronic state [16.7]0.5 has been identified in NiD, with no obvious analogue in NiH. The [16.7]0.5-$^2\Sigma^+_{1/2}$ and [16.7]0.5-$^2\Pi_{1/2}$ transitions proved to be a rich source of information about the two lower states

Observing quantum monodromy: an energy-momentum map built from experimentally-determined level energies obtained from the ⱱ7 far-infrared band system of ncncs

The concept of Quantum Monodromy (QM) provides a fresh insight into the structure of rovibrational levels in those flexible molecules for which a bending mode can carry the molecule through the linear configuration. To confirm the existence of QM in a molecule required the fruits of several strands of development: the formulation of the abstract mathematical concept of monodromy, including the exploration of its relevance to systems described by classical mechanics and its manifestation in quantum molecular applicationsthe development of the required spectroscopic technology and computer-aided assignmentand the development of a theoretical model to apply in fitting to the observed data. We present a timeline for each of these strands, converging in our initial confirmation of QM in NCNCS from pure rotational data alone.\footnote{B. P. Winnewisser \emph{et al.}, Phys. Rev. Lett. \textbf{95}, 243002 (2005).} In that work a Generalised SemiRigid Bender (GSRB) Hamiltonian was fitted to the experimental rotational structure. Rovibrational energies calculated from the fitted GSRB parameters allowed us to construct an ``Energy-Momentum" map and confirm the presence of QM in NCNCS. In further experimental work at the Canadian Light Source Synchrotron we have identified a network of transitions directly connecting the relevant energy levels and thereby have produced a refined Energy Momentum map for NCNCS from experimental measurements alone. This map extends from the ground vibrational level to well above the potential energy barrier, beautifully illustrating the characteristic signature of QM in a system uncomplicated by interaction with other vibrational modes

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Spectroscopy of the X1Σ+, a1π and B1Σ+ electronic states of mgs

The spectra of some astrophysical sources contain signatures from molecules containing magnesium or sulphur atoms. Therefore, we have extended previous studies of the diatomic molecule \chem{MgS}, which is a possible candidate for astrophysical detection. Microwave spectra of X$^1\Sigma^+$ , the ground electronic state, were reported in 1989\footnote{S. Takano, S. Yamamoto and S. Saito, Chem. Phys. Lett. \textbf{159}, 563-566 (1989).} and 1997\footnote{K. A. Walker and M. C. L. Gerry, J. Mol. Spectrosc \textbf{182}, 178-183 (1997).}, and the B$^1\Sigma^+$--X$^1\Sigma^+$ electronic absorption spectrum in the blue was last studied in 1970\footnote{M. Marcano and R. F. Barrow, Trans. Faraday Soc. \textbf{66}, 2936-2938 (1970).}. We have investigated the B$^1\Sigma^+$--X$^1\Sigma^+$ 0-0 spectrum of \chem{MgS} at high resolution under jet-cooled conditions in a laser-ablation molecular source, and have obtained laser-induced fluorescence spectra from four isotopologues. Dispersed fluorescence from this source identified the low-lying A$^1\Pi$ state near 4520 \wn. We also created \chem{MgS} in a Broida oven, with the help of a stream of activated nitrogen, and took rotationally resolved dispersed fluorescence spectra of the B$^1\Sigma^+$--A$^1\Pi$ transition with a grating spectrometer by laser excitation of individual rotational levels of the B$^1\Sigma^+$ state via the B$^1\Sigma^+$--X$^1\Sigma^+$ transition. These spectra provide a first observation and analysis of the A$^1\Pi$ state

Observation of the 4f\u21923d\u3c3 transition of the ArH molecule

The emission spectrum of ArH contains a band near 10 110 cm\u20131 that appears to be the analogue of the 3d \u2013 4p, v = 0 \u2013 0, band of ArD, observed and analysed near 10 230 cm\u20131. However, previous attempts to assign the rotational structure of this band of ArH were unsuccessful. Here we observe and analyse the 4f \u2013 3d band of ArH near 4400 cm\u20131, and are then able to calculate the rotational structure of the 3d \u2013 4p transition entirely from known data. The observed band is similar but not identical to the calculated band. We speculate that the observed spectrum is a v \u2013 v sequence band of 3d \u2013 4p, where the v 0 upper state is populated through some mechanism peculiar to this isotopomer.Le spectre d'\ue9mission de ArH contient une bande pr\ue8s de 10 110 cm\u20131 qui semble \ueatre l'analogue de la bande 3d \u2013 4p, v = 0 \u2013 0 de ArD observ\ue9e pr\ue8s de 10 230 cm\u20131. Les tentatives pr\ue9c\ue9dentes pour identifier la nature rotationnelle de cette bande ont \ue9chou\ue9. Ici, nous \ue9tudions la bande 4f \u2013 3d de ArH pr\ue8s de 4400 cm\u20131 et sommes alors capables de calculer la structure rotationnelle de la transition 3d \u2013 4p \ue0 partir de donn\ue9es connues. La bande observ\ue9e est similaire \ue0 celle calcul\ue9e, mais pas identique. Nous sp\ue9culons que le spectre observ\ue9 est une s\ue9quence v \u2013 v de 3d \u2013 4p o\uf9 l'\ue9tat sup\ue9rieur v 0 est peupl\ue9 via un m\ue9canisme particulier \ue0 cet isotopom\ue8re.NRC publication: Ye

Resolved fluorescence spectra of NiH. Electronic structure, electronic energy transfer, and the Zeeman effect in low-lying states

International audienc

CONTINUATION OF THE PURSUIT OF THE FAR-INFRARED SPECTRUM OF NCNCS, AT THE CANADIAN LIGHT SOURCE

Author Institution: Department of Physics, The Ohio State University, Columbus Ohio, 43210-1106, USA; Department of Physics and Centre for Laser, Atomic, and; Molecular Sciences, University of New Brunswick, P.O. Box 4400; Fredericton NB E3B 5A3, Canada; Canadian Light Source Inc., University of Saskatchewan; 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4,CanadaThe molecule cyanogen iso-thiocyanate, NCNCS, has proved to be the most revealing model system for studying the effects of molecular quantum monodromy, S.~C.~Ross~and~J.~Koput, Phys. Chem. Chem. Phys., {\bf 12}, 8158 (2010)}. In two previous measuring campaigns in May 2011 and May 2012 at the Canadian Light Source (CLS) at the University of Saskatchewan we have obtained a rich collection of high-resolution infrared band systems for both S(CN)$_{2}$ and its isomer NCNCS which is our target molecule. We found experimentally that NCNCS is the more stable isomer. Some results for S(CN)$_{2}$ are reported in the adjacent talk in this session. However, the isomerization between S(CN)$_{2}$ and NCNCS and other reaction products make the attainment of a pure sample of NCNCS difficult and time consuming. We have not yet obtained a satisfactory high-resolution recording of the quasi-linear bending mode in the far infrared in the two allotments of beam time so far available to us. Our theoretical preparations for the project include recent refinements of predictions of intensities in the low-lying bending mode band system, which will be shown. The experimental aspects of obtaining an optimal sample of NCNCS in order to observe the rotational resolved spectrum in the CLS campaign scheduled for May 2013, and an initial report of the results, will also be discussed