Investigation of the rotational spectrum of CD3_3OD and an astronomical search toward IRAS 16293−-2422

Solar-type prestellar cores and protostars display large amounts of deuterated organic molecules. Recent findings on CHD$_2$OH and CD$_3$OH toward IRAS 16293-2422 suggest that even fully deuterated methanol, CD$_3$OD, may be detectable as well. However, searches for CD$_3$OD are hampered in particular by the lack of intensity information from a spectroscopic model. The objective of the present investigation is to develop a spectroscopic model of CD$_3$OD in low-lying torsional states that is sufficiently accurate to facilitate searches for this isotopolog in space. We carried out a new measurement campaign for CD$_3$OD involving two spectroscopic laboratories that covers the 34 GHz-1.1 THz range. A torsion-rotation Hamiltonian model based on the rho-axis method was employed for our analysis. Our resulting model describes the ground and first excited torsional states of CD$_3$OD well up to quantum numbers $J \leq 51$ and $K_a \leq 23$. We derived a line list for radio-astronomical observations from this model that is accurate up to at least 1.1 THz and should be sufficient for all types of radio-astronomical searches for this methanol isotopolog. This line list was used to search for CD$_3$OD in data from the Protostellar Interferometric Line Survey of IRAS 16293$-$2422 obtained with the Atacama Large Millimeter/submillimeter Array. While we found several emission features that can be attributed largely to CD$_3$OD, their number is still not sufficiently high enough to establish a clear detection. Nevertheless, the estimate of 2$\times 10^{15}$ cm$^{-2}$ derived for the CD$_3$OD column density may be viewed as an upper limit that can be compared to column densities of CD$_3$OH, CH$_3$OD, and CH$_3$OH. The comparison indicates that the CD$_3$OD column density toward IRAS 16293-2422 is in line with the enhanced D/H ratios observed for multiply deuterated complex organic molecules.Comment: 10 pages total, including figures, tables, and references; abstract slightly shortened; Astron. Astrophys., accepte

Standing waves for acoustic levitation

Standing waves are the most popular method to achieve acoustic trapping. Particles with greater acoustic impedance than the propagation medium will be trapped at the pressure nodes of a standing wave. Acoustic trapping can be used to hold particles of various materials and sizes, without the need of a close-loop controlling system. Acoustic levitation is a helpful and versatile tool for biomaterials and chemistry, with applications in spectroscopy and lab-on-a-droplet procedures. In this chapter, multiple methods are presented to simulate the acoustic field generated by one or multiple emitters. From the acoustic field, models such as the Gor'kov potential or the Flux Integral are applied to calculate the force exerted on the levitated particles. The position and angle of the acoustic emitters play a fundamental role, thus we analyse commonly used configurations such as emitter and reflector, two opposed emitters, or arrangements using phased arrays

Enantiomers of the muscarinic antagonist 1-cyclohexyl-1-(4-fluorophenyl)-4-piperidino-1-butanol (p-fluoro-hexahydro-difenidol): synthesis, absolute configuration, and enantiomeric purity

The enantiomers of the antimuscarinic agent 1-cyclohexyl-1- (4-fluorophenyl)-4-piperidino-1-butanol [(R)- and (S)-p-fluorohexahydro- difenidol] ((R)- and (S)-2a] and their methiodides (R)- 3 and (S)-3 were prepared with high enantiomeric purity. (R)- 2a and (S)-2a (isolated as hydrochlorides) were obtained by catalytic hydrogenation (Pd/C contact) of the corresponding enantiomers of 1-cyclohexyl-1-( 4-fl uorophen yl)-4-piperidino- 2-butyn-1-ol [(R)- and (S)-4]. Reaction of (R)-2a and (S)-2a with rnethyl iodide led to (R)-3 and (S)-3, respectively. The unsaturated precursors (R)- and (S}-4 (enantiorneric purity ~ 99.80 and ~99.94% e.e.; calorimetric analysis) were prepared by res-sepaolution of rac-4 [available from 4-FC$_6$H$_4$C(O)C$_6$H$_{11}$ by reaction with LiC ~ CCH$_2$NC$_5$H$_{10}$] using (R)- and (S)-mandelic acid as resolving agents. The absolute configurations of the (R) and (S) enantiomers of 2a, 3, and 4 were determined by an X-ray crystal-structure analysis of (S)-5, the methiodide of (S)-4. (R)- 2a and (R)-3 exhibit a higher affinity for muscarinic M1, M2, M3, and M4 receptors (by up to two orders of magnitude) than their corresponding antipodes (S)-2a and (S)-3, the degree of stereoselectivity depending on the receptor subtype involved. (R)-2a represents a useful tool for rnuscarinic receptor research (affinity profile: M1 ~ M3 ~ M4 > M2)

THE ZURICH HIGH RESOLUTION COLLISIONAL-COOLING CELL-FTIR SETUP: ROVIBRATIONAL SPECTROSCOPY OF METHANOID MOLECULES BETWEEN 60 AND 300 K

Author Institution: Physical Chemistry, ETH Zurich, CH-8093 Zurich, SwitzerlandA complete understanding of the absorption behavior of the Earth's atmosphere and of the atmospheres of the giant planets (Saturn and Jupiter) and their moons (Titan) requires a detailed spectroscopic investigation of methanoid molecules over full atmospheric temperature ranges. For that reason we have interfaced a collisional and enclosive cooling cell} in press.} based on White-type multireflection optics to our FTIR IFS125 HR prototype 2001 spectrometer}, {\it Trends in Optics and Photonics} {\bf 84}, 177 (2003).} (MOPD=10 m). This cell makes it possible to record spectra at high spectral resolution in the temperature range 4-400 K with absorption path lengths up to 20 m. We have recorded the spectra of CH$_4$} and its isotopomers} and of CHF$_3$}, CHClF$_2$} {\bf 102}, 1671 (2004).} and CHCl$_2$F$^a$ between 2000 and 6000 cm$^{-1}$ in the temperature range 60-300 K. The spectra were recorded at resolutions ranging from 0.0015 to 0.004 cm$^{-1}$. We will present an analysis of the spectra of CHCl$_2$F in the $2\nu_3$ and $3\nu_3$ regions and an initial assignment of the resonance system $2\nu_3/\nu_3 +\nu_8/2\nu_8$ of CHClF$_2$. We discuss coincidences with CO$_2$ laser lines in the $2\nu_3$ region of the isotopic chiral molecule CH$^{35}$Cl$^{37}$ClF. Doppler-free quasi-resonantly enhanced ultra-high two-photon absorption experiments may be carried out in this region to study parity violation} {\bf 114}, 4812 (2002), M. Quack and J. Stohner, {\it J. Chem. Phys.} {\bf 119}, 11228 (2003), R. Berger, G. Laubender, M. Quack, A. Sieben, J. Stohner and M. Willeke, {\it Angew. Chem. Int. Ed. Eng.} {\bf 44}, 3623 (2005).} in this molecule. In addition, we show CO nanoparticles recorded at 6 K } {\bf 72}, 3946 (2001).}

STEPS TOWARD EXPERIMENTAL DETECTION OF MOLECULAR PARITY VIOLATION: ROVIBRATIONAL ANALYSIS OF THE CF-STRETCHING MODE AND FIRST OVERTONE OF CHFBrI

M.~Quack, J.~Stohner and M.~Willeke, \emph{Annu.~Rev.~Phys.~Chem.M.~Quack and J.~Stohner, \emph{PRLJ.K.~Laerdahl, P.~Schwerdtfeger and H.M.~Quiney, \emph{PRLC.~Daussy, T.~Marrel, A.~Amy-Klein, C.~Nguyen, C.~Borde and C.~Chardonnet, \emph{Phys.~Rev.~Lett.S.~Albert and M.~Quack, \emph{ChemPhysChemD.~T.~Petkie, T.~M.~Goyette, R.~P.~A.~Bettens, S.~P.~Belov, S.~Albert, P.~Helminger and F.~C.~De~Lucia, \emph{Rev. Sci. Instr.F.~Lewen, R.~Gendriesch, I.~Pak, D.G.~Paveliev, M.~Hepp, R.~Schieder and G.~Winnewisser, \emph{Rev.~Sci.~Instrum.Author Institution: PHYSICAL CHEMISTRY, ETH ZURICH, CH-8093 ZURICH, SWITZERLAND; INSTITUT FUR TECHNISCHE UND PHYSIKALISCHE CHEMIE, TU BRAUNSCHWEIG; D-38106 BRAUNSCHWEIG, GERMANYThe experimental detection of molecular parity violation \textbf{2008}, \emph{59}, 741, A.~Bakasov, T.K.~Ha and M.~Quack, \emph{J.~Chem.~Phys.} \textbf{1998}, \emph{109}, 7263, R.~Berger and M.~Quack, \emph{J.~Chem.~Phys.} \textbf{2000}, \emph{112}, 3148.} $\Delta_{PV}E$ is of great interest because of its importance in the understanding of fundamental aspects of molecular dynamics and symmetries. One possible method for this is measuring the rovibrational or rotational frequency shifts in the infrared or microwave spectra of enantiomers \textbf{2000}, \emph{84}, 3807, M.~Quack and J.~Stohner. \emph{J.~Chem.~Phys.} \textbf{2003}, \emph{119}, 11228.}. A value of 50~mHz is predicted for vibrational frequency shifts in CHFBrI \textbf{2000}, \emph{84}, 3811, R.~Berger and J.L.~Stuber, \emph{Mol.~Phys.} \textbf{2007}, \emph{105}, 41.}, which is almost within the range of current infrared \textbf{1999}, \emph{83}, 1554} and submm wave spectroscopic resolution. We report here IR-spectroscopic results and a first high resolution analysis of the infrared spectrum of CHFBrI. The FTIR spectrum of CHFBrI was recorded at 190~K and 295~K in the regions 600--1300~cm$^{-1}$ and 1800--2350~cm$^{-1}$ \textbf{2007}, \emph{8}, 1271.}. We were able to analyse the rovibrational spectra of CHF$^{79}$BrI ($\nu_0$ = 1060.81569~cm$^{-1}$) and CHF$^{81}$BrI ($\nu_0$ = 1060.77864~cm$^{-1}$) in the CF-stretching ($\nu_6$) and its overtone regions with band centers $\nu_0$ = 2103.75730~cm$^{-1}$ for CHF$^{79}$BrI and $\nu_0$ = 2103.65974~cm$^{-1}$ for CHF$^{81}$BrI. We will discuss a possible application of CO$_2$ laser quasi-resonant two photon transitions in the overtone region of CHFBrI. Finally, we will show submm spectra of CHFBrI recorded with the Zurich-FASSST spectrometer and discuss how submm wave spectroscopy based on FASSST \textbf{1997}, \emph{68}, 1675.} and phase-locked backward wave oscillators \textbf{1998}, \emph{69}, 32.} can be used to determine line shifts on the order of mHz

Spectroscopic characterization of N 2 O aggregates: from clusters to the particulate state

Abstract Collisional cooling is used to generate N 2 O particles with radii ranging from the subnanometer to the submicrometer region. The vibrational dynamics of the aggregates is studied by Fourier transform infrared spectroscopy. In the region of the stretching fundamentals and combination bands, the infrared spectra of the particles exhibit characteristic sizedependent features. For the very small particles, the results obtained from collisional cooling are compared for the first time with corresponding results from supersonic jet expansions. It turns out that with both methods very similar clusters are generated. A pronounced temperature dependence of a combination band maximum in the collisional cooling cell spectra is found. This correlation is exploited to estimate cluster temperatures in supersonic jet spectra.