High resolution infrared spectroscopy of slit-jet cooled van der Walls ocs clusters

Bibliography: p. 167Includes copies of co-author permission forms. Original copies with original Partial Copyright Licence form

Isotope effects in the infrared spectrum of the OCS dimer

Infrared spectra of 34S and 13C isotopes of the OCS dimer are studied in the 2015-2075?cm-1 region using a tunable laser to probe a pulsed supersonic expansion. The spectrum of (16O12C34S)2 is similar to that of the normal isotope, but that of (16O13C32S)2 differs due to nuclear spin statistics and due to small (<0.01?cm-1) rotational perturbations whose nature is not entirely clear. The shift of the (16O13C32S)2 band origin relative to 16O13C32S is significantly smaller than predicted by scaling from the normal isotope. It was not possible to detect spectra of isotopically mixed dimers.NRC publication: Ye

Observation of the "missing" polar OCS dimer

A new infrared band at 2069.3 cm-1 is observed and assigned to the long-anticipated polar isomer of the OCS dimer, helping to explain apparent discrepancies among earlier studies. The data reported here should enable direct observation of the microwave spectrum of polar (OCS)2 and motivate new theoretical works on the energetics of OCS dimer isomers and interconversion energy barriers.Peer reviewed: YesNRC publication: Ye

Nitrous oxide dimer : observation of a new polar isomer

Spectra of the nitrous oxide dimer (N2O)2 are studied in the region of the N2O nu1 fundamental band around 2230 cm?1 using a rapid-scan tunable diode laser spectrometer to probe a pulsed supersonic jet expansion. The previously known band of the centrosymmetric nonpolar dimer is analyzed in improved detail, and a new band is observed and assigned to a polar isomer of (N2O)2. This polar form of the dimer has a slipped parallel structure, rather similar to the slipped antiparallel structure of the nonpolar form but with a slightly larger intermolecular distance. The accurate rotational parameters determined here should enable a microwave observation of the polar N2O dimer. The need for a modern ab initio investigation of the N2O\ufffdN2O intermolecular potential energy surface is emphasized.Peer reviewed: YesNRC publication: Ye

Isolation of keratinophilic fungi from the soil of islands of Greater Tunb, Abu-Musa and Sirri, Persian Gulf, Iran

Background and Purpose: Keratinophilic fungi are among the important groups of fungi living in the soil. This study aimed to isolate and identify keratinophilic fungi from the soil of three Iranian islands, namely Greater Tunb, Abu Musa, and Sirri, located in the Persian Gulf using morphological and molecular (polymerase chain reaction) methods. Materials and Methods: In this study, a total of 60 soil samples were collected from the three islands of Greater Tunb, Abu Musa, and Sirri. The samples were analyzed for the presence of the keratinophilic fungi using a hair baiting technique. Furthermore, the identification of keratinophilic fungi was accomplished through the employment of molecular and sequencing techniques. Results: A total of 130 fungal isolates, including 11 genera with 24 species, were collected. Accordingly, Chrysosporium tropicum (24;18.5%), C. keratinophilum (17; 13.1%),&nbsp; Chrysosporium&nbsp; species (15; 11.5%), Aspergillus&nbsp; species ( 8;6.1%), Aspergillus flavus (8; 6.1%), Penicillium&nbsp; species (8;6.1%), Alternaria spp ( 6; 4.6%), Phoma&nbsp; species (5;&nbsp; 3.8%), Aphanoascus verrucosus (4;3.1%), Fusarium chlamydosporum (4; 3.1%), Aspergillus trreus (4;3.1%), Acremonium&nbsp; species (4; 3.1%), and other fungi( 23; 17.8 %) isolates were identified . All isolates of keratinophilic fungi were isolated from the soils with the pH range of 7-9. Conclusion: The results of this study contributed towards a better conceptualization of the incidence pattern of keratinophilic fungi in the regions of Iran. Given that no study has investigated this issue, the findings of the present study can be beneficial for the management of public health surveillance, physicians, and epidemiologists.&nbsp;&nbsp

Infrared spectra of OCS-C6H6, OCS-C6H6-He, and OCS-C6H6-Ne van der Waals complexes

The infrared spectrum of weakly bound OCS\u2013C6H6 is studied in the region of the \u3bd1 fundamental band of OCS ( ~ 2050\u2002cm 121) using a tunable diode laser spectrometer to probe a pulsed supersonic jet expansion. This is one of the first direct infrared observations of a benzene-containing van der Waals complex. A very simple band is observed, corresponding to the parallel transition of a symmetric top. It is shifted by 1211.1\u2002cm 121 with respect to the free OCS monomer. The isotopologues OCS\u201313C\u200912C5H6 and OC\u200934S\u2013C6H6 are observed, and the derived structure has OCS located along the benzene C6 symmetry axis in an S-bonded configuration with a center of mass separation of 4.42 \uc5, in good agreement with previous microwave spectra. Similar bands are observed for the trimers OCS\u2013C6H6\u2013He and OCS\u2013C6H6\u2013Ne, whose structure is obtained by adding an on-axis rare gas atom to the other side of the benzene. However, the analogous band for OCS\u2013C6H6\u2013Ar is not detected, raising the possibility that the stable form of this trimer may not have the same symmetrical structure. A \u201cmystery\u201d feature is observed close to the OCS\u2013C6H6 band origin and its possible assignment to a cluster such as OCS\u2013(C6H6)3 is discussed.Peer reviewed: YesNRC publication: Ye

NEW INFRARED SPECTRA OF THE NITROUS OXIDE TRIMER

Author Institution: Department of Physics and Astronomy, University of Calgary; Calgary, AB T2N 1N4, CANADA; Steacie Institute for Molecular Sciences, National Research; Council of Canada, Ottawa, ON K1A 0R6, CANADAInfrared spectra of N$_{2}$O trimers are studied using a tunable diode laser to probe a pulsed supersonic slit-jet expansion. A previous observation by R.E. Miller and L. Pedersen [J. Chem. Phys. \textbf{108}, 436 (1998)] in the N$_{2}$O \nub{1}+\nub{3} combination band region (~3480 cm$^{-1}$) showed the trimer structure to be noncyclic, with three inequivalent N$_{2}$O monomer units which could be thought of as an N$_{2}$O dimer (slipped antiparallel configuration) plus a third monomer unit lying above the dimer plane. The present observations cover the N$_{2}$O fundamental band regions \nub{3} (~1280 cm$^{-1}$) and \nub{1} (~2230 cm$^{-1}$). In the \nub{3} region, two trimer bands are assigned with vibrational shifts and other characteristics similar to those in the \nub{1}+\nub{3} region, but in the \nub{1} region all three possible trimer bands are observed. Relationships among the various bands such as rotational intensity patterns, vibrational shifts, and the properties of the related N$_{2}$O dimer, generally support the conclusions of Miller and Pedersen. Three trimer bands are also observed for the fully$\ ^{15}$N-substituted species in the \nub{1} region, and these results should aid in detection of the as-yet-unobserved pure rotational microwave spectrum of the trimer. Finally, three combination bands involving the intermolecular van der Waals modes at 2253.7, 2255.5, and 2269.4 cm$^{-1}$ have been measured. The analyses of these bands and the identification of the nature of the intermolecular modes involved are currently underway