Chirped pulse rotational spectroscopy of a single thujone+water sample

Rotational spectroscopy of natural products dates over 35 years when six different species including thujone were investigated.\footnote{Z.Kisiel, A.C.Legon, {\it JACS} {\bf 100}, 8166 (1978).} Nevertheless, the technique of low-resolution microwave spectroscopy employed therein allowed determination of only a single conformational parameter. Advances in sensitivity and resolution possible with supersonic expansion techniques of rotational spectroscopy made possible much more detailed studies such that, for example, the structures of first camphor,\footnote{Z.Kisiel, O.Desyatnyk, E.Bia\l kowska-Jaworska, L.Pszcz\' o\l kowski, {\it PCCP} {\bf 5} 820 (2003).} and then of multiple clusters of camphor with water\footnote{C.P\'erez, A.Krin, A.L.Steber, J.C.L\'opez, Z.Kisiel, M.Schnell, {\it J.Phys.Chem.Lett.} {\bf 7} 154 (2016).} were determined. \vspace{0.2cm} We revisited the rotational spectrum of the well known thujone molecule by using the chirped pulse spectrometer in Hamburg. The spectrum of a single thujone sample was recorded with an admixture of $^{18}$O enriched water and was successively analysed using an array of techniques, including the AUTOFIT program,\footnote{N.A.Seifert, I.A.Finneran, C.Perez, et al. {\it J.Mol.Spectrosc.} {\bf 312}, 12 (2015).} the AABS package\footnote{Z.Kisiel, L.Pszcz\'o\l kowski, B.J.Drouin, et al. {\it J.Mol.Spectrosc.} {\bf 280}, 134 (2012).} and the STRFIT program.\footnote{Z.Kisiel, {\it J.Mol.Spectrosc.} {\bf 218}, 58 (2003).} We have, so far, been able to assign rotational transitions of $\alpha$-thujone, $\beta$-thujone, another thujone isomer, fenchone, and several thujone-water clusters in the spectrum of this single sample. Natural abundance molecular populations were sufficient to determine precise heavy atom backbones of thujone and fenchone, and H$_2$$^{18}$O enrichment delivered water molecule orientations in the hydrated clusters. An overview of these results will be presented

Rotational spectroscopy of cf2clccl3 and analysis of hyperfine structure from four quadrupolar nuclei

CF$_2$ClCCl$_3$ has recently been identified among several new ozone- depleting substances in the atmosphere.\footnote{J.C.Laube, M.J.Newland, C.Hogan, et al., {\it Nature Geoscience} {\bf 7}, 266 (2014).} There are no literature reports concerning rotational spectroscopy of this molecule, although we were recently able to report its first chirped pulse, supersonic expansion spectrum.\footnote{Z.Kisiel, E.Bia\l kowska-Jaworska, L.Pszcz\'o\l kowski, I.Uriarte, P.Ejica, F.J.Basterretxea, E.J.Cocinero, 70$^{th}$ ISMS, Champaign-Urbana, Illinois, RF-11 (2015).} CF$_2$ClCCl$_3$ has a rather small dipole moment so that the spectrum is weak and each transition displays very complex nuclear quadrupole hyperfine structure resulting from the presence of four chlorine nuclei. \vspace{0.2cm} We have presently been able to carry out a complete analysis of the hyperfine structure by combining the information from chirped pulse spectra with dedicated higher resolution measurements made with a cavity supersonic expansion instrument. The hyperfine analysis was carried out with Pickett's SPFIT/SPCAT package and the sizes of Hamiltonian matrices are sufficiently large to require the use of 64-bit compilation of these programs (made available for both Windows and Linux systems on the PROSPE website). The resulting fit is to within experimental accuracy and is supported by $ab~initio$ calculations. The precise values of off-diagonal hyperfine constants for all nuclei lead to useful angular information that is complementary to direct structural information from moments of inertia.\footnote{Z.Kisiel, E.Bia\l kowska-Jaworska, L.Pszcz\'o\l kowski, {\it J.Chem.Phys.} {\bf 109}, 10263 (1998).

Further analysis of the laboratory rotational spectrum of CH3NCO

Identification by the Rosetta mission that CH$_3$NCO is among the more plentiful molecules on the surface of the comet Churyumov-Gerasimenko stimulated rapid detection of this molecule in the interstellar medium.\footnote{D.T.Halfen, V.V.Ilyushin, L.Ziurys, {\it ApJ} {\bf 812}, L5 (1915).}$^,$\footnote{J.Cernicharo, Z.Kisiel, B.Tercero, et al., {\it A\&A} {\bf 587}, L4 (2016).} In particular, we have been successful in detecting almost 400 lines of CH$_3$NCO in Orion$^b$ by extending the Koput\footnote{J.Koput, {\it J.~Mol.~Spectrosc.} {\bf 115}, 131 (1986).} cm-wave assignment to frequencies relevant to mm-wave radio-telescopes through measurement of the complete laboratory spectrum up to 363 GHz.$^{b,}$\footnote{Z.Kisiel et al., 65$^{th}$ ISMS, Columbus, Ohio, RC-13 (2010)\, 70$^{th}$ ISMS, Champaign-Urbana, Illinois, TG-08 (2015).} \vspace{0.2cm} Presently, we describe further progress in understanding the laboratory rotational spectrum of CH$_3$NCO. Assignment has been extended to transitions with $K>3$ by analysis of Stark and hyperfine patterns of the corresponding lowest-$J$ transitions. Broadband spectra of synthezised pure $^{13}$CH$_3$NCO and CH$_3$N$^{13}$CO isotopic species have also been recorded and assigned. Furthermore, the progress in fitting this very low barrier and highly perturbed internal rotation spectrum is described

LOWEST VIBRATIONAL STATES OF ACRYLONITRILE

Recent studies of the broadband rotational spectrum of acrylonitrile, H$_2$C=CHC$equiv$N, revealed the presence of multiple resonances between rotational levels in different vibrational states. The resonances affect even the ground state transitions and their analysis allowed determination of vibrational term values for the first three excited states above the ground statefootnote{Z. Kisiel, et al., {it J. Mol. Spectrosc.} {bf 280} 134 (2012).} and of vibrational energy differences in several polyads above these states.footnote{A. L'opez, et al., {it Astron. & Astrophys.} {bf 572}, A44 (2014).} At that time there was no infrared data of sufficient resolution to assess the reliability of the resonance based vibrational energy determinations. vspace{0.2cm} We presently report results based on a 40-700 cm$^{-1}$ high-resolution spectrum of acrylonitrile recorded at the AILES beamline of the SOLEIL synchrotron. This spectrum was reduced by using the AABS package$^{a,}$footnote{Z. Kisiel, et al., {it J. Mol. Spectrosc.} {bf 233} 231 (2005).} and allowed assignment of vibration-rotation transitions in four fundamentals, five hot bands, and one overtone band. The infrared data and previous measurements made with microwave techniques have been combined into a single global fit encompassing over 31000 measured transitions. Precise vibrational term values have been determined for the eight lowest excited vibrational states. The new results validate the previous estimates from rotational perturbations and are also compared with results of {it ab~initio} anharmonic force field calculations

THE COMPLETE ROTATIONAL SPECTRUM OF CH3NCO UP TO 376 GHz

The methylisocyanate molecule, CH$_3$NCO, is of interest as a potential astrophysical species and as a model system for the study of quasisymmetric behavior. The rotational spectrum is made very complex by the presence in CH$_3$NCO of two large-amplitude motions: an almost free internal rotation and a low barrier skeletal bending motion. This challenging spectrum has, nevertheless, been assigned at 8-38 GHz by Stark spectroscopyfootnote{J.Koput, {it J.~Mol.~Spectrosc.} {bf 115}, 131 (1986).} and has been measured at 117-376 GHz with the broadband FASSST technique.footnote{Z.Kisiel et al., 65$^{th}$ OSU Symposium on Molecular Spectroscopy, The Ohio State University, Ohio 2010, RC-13.} vspace{0.2cm} We presently report the results of measuring this spectrum also in supersonic expansion for the transitions below 40 GHz, and at room-temperature in the region between 40 and 120 GHz. In this way we are finally able to confirm the assignment of the ground state and of the internal rotation $m$=1 state and to analyse the nitrogen hyperfine splitting structure. It is also possible to confidently transfer the Stark-based assignment to the transition sequences measured in the mm-wave region, and to assign high $K_a$ sequences. Various models for fitting this spectrum are explored but, even without more extensive fits, we are now able to present temperature scalable linelists for astrophysical applications

ROTATIONAL SPECTROSCOPY OF NEWLY DETECTED ATMOSPHERIC OZONE DEPLETERS: CF3CH2Cl, CF3CCl3, AND CF2ClCCl3

In a recent study of unpolluted air samples from Tasmania and of deep firn snow in Greenland four previously overlooked ozone-depleting substances have been identified.footnote{J.C.Laube, et al., {it Nature Geoscience} {bf 7}, 266 (2014).} These compounds started to emerge in the atmosphere in the 1960s, and two: CF$_3$CCl$_3$ (CFC-113a) and CF$_3$CH$_2$Cl (HCHF-133a) continue to accumulate in the atmosphere. vspace{0.2cm} Three of the four compounds have non-zero dipole moments and are amenable to study by rotational spectroscopy, establishing the basis for analytic applications. Relatively limited studies have been reported for CF$_3$CH$_2$Clfootnote{T.Ogata, et al., {it J. Mol. Struct.} {bf 144}, 1 (1986).} and CF$_3$CCl$_3$,footnote{R.Holm, et al., {it Z. Naturforsch.} {bf 23a}, 1040 (1968).}$^,$footnote{J.H.Carpenter et al., {it J. Mol. Spectrosc.} {bf 154}, 207 (1992); P.J.Seo et al., {it J. Mol. Spectrosc.} {bf 169}, 58 (1995).} while CF$_2$ClCCl$_3$ has not yet been studied by this technique. We presently report extensive results obtained for all three compounds, resulting from concerted application of supersonic expansion FTMW spectroscopy in chirped pulse and cavity modes, and room-temperature MMW spectroscopy. Among the plentiful results, we have been able to resolve and fit the complex nuclear quadrupole hyperfine splitting

Trends in assembling of advanced IC packages, Journal of Telecommunications and Information Technology, 2005, nr 1

In the paper, an overview of the current trends in the development of advanced IC packages will be presented. It will be shown how switching from peripheral packages (DIP, QFP) to array packages (BGA, CSP) and multichip packages (SiP, MCM) affects the assembly processes of IC and performance of electronic systems. The progress in bonding technologies for semiconductor packages will be presented too. The idea of wire bonding, flip chip and TAB assembly will be shown together with the boundaries imposed by materials and technology. The construction of SiP packages will be explained in more detail. The paper addresses also the latest solutions in MCM packages

Measurement of CH3_3D on Titan at Submillimeter Wavelengths

We present the first radio/submillimeter detection of monodeuterated methane (CH$_3$D) in Titan's atmosphere, using archival data from of the Atacama Large Millimeter/submillimeter Array (ALMA). The $J_K=2_1-1_1$ and $J_K=2_0-1_0$ transitions at 465.235 and 465.250 GHz ($\sim0.644$ mm) were measured at significance levels of $4.6\sigma$ and $5.7\sigma$, respectively. These two lines were modeled using the Non-linear optimal Estimator for MultivariatE spectral analySIS (NEMESIS) radiative transfer code to determine the disk-averaged CH$_3$D volume mixing ratio = $6.157\times10^{-6}$ in Titan's stratosphere (at altitudes $\gt130$ km). By comparison with the CH$_4$ vertical abundance profile measured by Cassini-Huygens mass spectrometry, the resulting value for D/H in CH$_4$ is $(1.033\pm0.081)\times10^{-4}$. This is consistent with previous ground-based and in-situ measurements from the Cassini-Huygens mission, though slightly lower than the average of the previous values. Additional CH$_3$D observations at higher spatial resolution will be required to determine a value truly comparable with the Cassini-Huygens CH$_4$ measurements, by measuring CH$_3$D with ALMA close to Titan's equator. In the post-Cassini era, spatially resolved observations of CH$_3$D with ALMA will enable the latitudinal distribution of methane to be determined, making this an important molecule for further studies.Comment: 9 pages, 4 figure

The effect of fasting and refeeding on the ultrastructure of the hypothalamic paraventricular nucleus in young and old rats

In order to explore the morphological basis of the altered feeding behaviour of old rats, an ultrastructural investigation of the magnocellular neurons of the hypothalamic paraventricular nucleus (PVN) was performed. Young and old male Wistar rats, 5 and 24 months old, respectively, and with each age group comprising 12 animals, were divided into 3 groups. The rats in Group I were used as controls (normally fed), the rats of Group II were fasted for 48 hours and in Group III the rats were fasted for 48 hours and then refed for 24 hours. The brains were fixed by perfusion and histological and ultrathin sections were obtained by routine methods. Common features of the magnocellular PVN neurons of young and old rats were abundant Golgi complexes and short fragments of RER localised at the cell periphery. In contrast to young rats, the PVN neurons of old animals showed deep indentations of the nuclear envelope and agerelated residual bodies. In both age groups fasting for 48 hours led to the expansion of the Golgi complexes and dilatation of RER cisternae. In contrast to those in fed rats, RER cisternae in the neurons of old fasted animals were situated between the nuclear envelope and the Golgi zone. Prolonged RER cisternae were distributed in the peripheral cytoplasm of refed old rats. Our observations suggest that at the ultrastructural level the process of ageing does not change the responsiveness of magnocellular PVN neurons to fasting-refeeding

Broadband Fourier transform rotational spectroscopy for structure determination: The water heptamer

Over the recent years chirped-pulse, Fourier-transform microwave (CP-FTMW) spectrometers have chan- ged the scope of rotational spectroscopy. The broad frequency and large dynamic range make possible structural determinations in molecular systems of increasingly larger size from measurements of heavy atom (13C, 15N, 18O) isotopes recorded in natural abundance in the same spectrum as that of the parent isotopic species. The design of a broadband spectrometer operating in the 2–8 GHz frequency range with further improvements in sensitivity is presented. The current CP-FTMW spectrometer performance is benchmarked in the analyses of the rotational spectrum of the water heptamer, (H2O)7, in both 2– 8 GHz and 6–18 GHz frequency ranges. Two isomers of the water heptamer have been observed in a pulsed supersonic molecular expansion. High level ab initio structural searches were performed to pro- vide plausible low-energy candidates which were directly compared with accurate structures provided from broadband rotational spectra. The full substitution structure of the most stable species has been obtained through the analysis of all possible singly-substituted isotopologues (H218O and HDO), and a least-squares rm(1) geometry of the oxygen framework determined from 16 different isotopic species compares with the calculated O–O equilibrium distances at the 0.01 Å level