ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    The vibrational spectrum and rotational constants of difluoroethyne FC 3/4 CF. Matrix and high resolution infrared studies and ab initio calculations (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 5660-5669 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Infrared spectra of the short-lived difluoroethyne molecule have been recorded in neon and argon matrices between 200 and 5000 cm−1. Fourier transform infrared spectra with a resolution of 0.004 cm−1 have been measured in the gas phase around 1350 cm−1 (ν3, ν2+ν4+ν5, hot bands) and 2150 cm−1 (ν2+ν3, ν1−ν5, hot bands). The high resolution study yields rotational parameters of the ground and all singly excited vibrational states. The interpretation of the experimental data has been guided by ab initio calculations at the SCF (self-consistent-field) level and the correlated MP2 level (Moller–Plesset second order perturbation theory) employing three different large basis sets. The theoretical calculations provide the SCF and MP2 harmonic fields as well as the SCF anharmonic force field of FCCF. The agreement between the available theoretical and experimental results is generally quite good, with the exception of the spectroscopic constants involving the trans-bending mode ν4 where more theoretical work is required. The combined use of theoretical and experimental information leads to an estimate of the equilibrium structure [D∞h, re(CC)=1.1865 A(ring), re(CF)=1.2832 A(ring)] and to recommended "best'' values for the wave numbers of all fundamental vibrations based on the matrix and high resolution infrared data and some ab initio anharmonicity constants. The present study demonstrates the advantages of a combined theoretical and experimental approach to the spectroscopy of short-lived molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.461640
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    High-resolution rotation–vibration spectroscopy of difluorophosphorane: A combined theoretical and experimental study (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 4603-4614 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The harmonic and anharmonic force fields of PH3F2 have been calculated at the ab initio self-consistent-field level using polarized split-valence and triple-zeta basis sets. PH3F2 has been prepared in pure form and identified unambiguously in the gas phase by Doppler-limited Fourier transform infrared spectroscopy. Guided by the theoretical predictions for the rotation–vibration spectra and the spectroscopic constants, the observed bands have been assigned and several of them rotationally analyzed, in particular ν4/2ν±27, ν2+ν4/ν2+2ν±27, and ν5/ν3+ν8. PH3F2 is found to have a D3h structure, ro(PH)=1.394(4) A(ring) and ro(PF)=1.6468(2) A(ring). The theoretical results are in good agreement with experiment, both for the structure and for the available spectroscopic constants. The present study demonstrates the advantages of a combined theoretical and experimental approach to the spectroscopy of reactive molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458700
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    State-selectivity of excited-state intramolecular proton transfer in a "double'' benzoxazole: Jet spectroscopy and semiempirical calculations (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 97 (1992), S. 3914-3919 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The fluorescence excitation spectra of free 2,5-bis(2'-benzoxazolyl)-hydroquinone (BBXHQ) cooled in a supersonic jet are examined. By using double-resonance saturation spectroscopy, we show that adjacent vibronic transitions, leading to either blue or red fluorescence, belong to a single molecular species in the electronic ground state. The molecular geometries of the enol and keto forms which are relevant for intramolecular transfer of a single hydrogen atom in the S1 state are obtained by the MNDO/H method. The translocation distance is calculated to be 0.43 A(ring). The complexity of the vibronic spectrum, near the electronic origin for the S0(1Ag) → S1(1Bu) transition of the enol form at 4178.1 A(ring), is attributed to vibronic coupling with the nonplanar excited keto form due to H tunneling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.462930
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Ab initio calculations on monohalogenophosphanes PH2X (X=F,Cl,Br,I), and experimental detection and characterization of PH2F and PH2Cl by high resolution infrared spectroscopy (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 101 (1994), S. 5585-5595 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The harmonic and anharmonic force fields of the title compounds have been calculated at the ab initio self-consistent-field level using effective core potentials and polarized double-zeta basis sets. Additional calculations for PH2F employ larger basis sets and include electron correlation. Many rovibrational constants are predicted theoretically. The infrared spectra generated from the ab initio data have guided the experimental identification of PH2F and PH2Cl in the gas phase. High resolution Fourier transform infrared spectra of these unstable molecules have been recorded for the first time. Rotational analyses for several bands are reported which provide accurate ground state constants and a precise characterization of a number of vibrationally excited states. The accuracy of the ab initio predictions for PH2F and PH2Cl is evaluated by comparisons with these experimental data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.468460
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The vibrational spectra of krypton and xenon difluoride: High-resolution infrared studies and ab initio calculations (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 101 (1994), S. 1-14 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Fourier transform infrared spectra of KrF2, XeF2, and monoisotopic 136XeF2 have been recorded in the ν3 and ν1+ν3 ranges with an effective resolution of 0.003–0.007 cm−1. About 10 000 rovibrational lines belonging to cold bands and to hot bands with ν1, ν2, 2ν2, and ν3 as lower levels have been assigned and fitted. The high-resolution results from this work and from two previous studies provide a rather complete set of precise spectroscopic constants and accurate ground-state and equilibrium geometries for both molecules. In the case of 84KrF2, r0=188.2821(9) pm supersedes previous incorrect r0 values, and re=187.6930(23) pm represents the first determination of the Kr–F equilibrium distance. Ab initio calculations employing effective core potentials and polarized double-zeta basis sets have been carried out at the following levels: self-consistent-field (SCF) theory, the Møller–Plesset second order perturbation theory (MP2), and coupled cluster theory with single and double excitations (CCSD) and a perturbational treatment of triple excitations (CCSD(T)). Pronounced correlation effects are found, especially for KrF2. The agreement between the correlated theoretical and the experimental results is generally quite good. A theoretical analysis clarifies the origin of the positive α2 vibration–rotation coupling constants which have been observed for the bending vibrations in both molecules. Reliable harmonic and anharmonic force fields are presented for KrF2 and XeF2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.468170
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Elastic electron deuteron scattering on a tensor polarized solid ND3 target (1991)
    Springer
    The European physical journal 49 (1991), S. 175-185 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Elastic electron deuteron scattering has been measured at the Bonn 2.5 GeV electron-synchrotron using a tensor polarized ND3 target. The scattered electrons and deuterons were detected in coincidence by two magnetic spectrometers. Data were taken at an average value of four momentum transfer ofQ 2=0.495 (GeV/c)2 in order to separate the electric monopole and quadrupole form factors of the deuteron. To have a sufficient control of systematic effects, both polarized and unpolarized cross sections were measured with an identical experimental set up. In the ratioR EXP=dσpol/dσunp systematic effects are expected to cancel. This ratioR EXP is related to the theoretical polarized cross section d dσ T where the spin quantization axis for the deuterons is orientated in the ed-scattering plane, perpendicular to the virtual photon direction. Our final result for the corresponding recoil tensor polarization ist 20=−2.01±1.13.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01555492
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Photoelectron spectroscopic investigation of perimidine derivatives (1990)
    Springer
    Structural chemistry 1 (1990), S. 367-370 
    Details
    ISSN: 1572-9001
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The Hel UPS spectra of acetamidine, perimidine, and four 2-substituted perimidine derivatives have been recorded and interpreted using ab initio and MNDO quantum-chemical calculations. A large interaction between the naphthalene and amidine fragment was concluded from the lowest ionization energy. The color-determining band of these compounds is strongly affected by the intramolecular charge-transfer transitions, which are of low energy because of the low ionization energy of the perimidine moiety.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01374484
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    4H-3,1-Benzothiazin-4-one aus Dithioestern und o-AminobenzoesäureHerrn Prof. Dr. habil. R. Mayer zum 65. Geburtstag gewidmet (1992)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 334 (1992), S. 92-94 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4H-3,1-Benzothiazin-4-ones from Dithicarboxylic Esters and o-Aminobenzoic Acid
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19923340119
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    1,3,4-Thiadiazole durch Umsetzung von Dithioestern mit KohlensäurehydrazidenHerrn Professor Schulz zum 60. Geburtstag gewidmet (1990)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 332 (1990), S. 55-64 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3,4-Thiadiazoles by Reaction of Dithiocarboxylic Esters with Carbonic Hydrazides1,1-Dithiooxalic esters 1 and heteroaryl dithiocarboxylic esters 2 react with carbonic hydrazides yielding 1,3,4-thiadiazoles. The 1-thiooxamoyl semicarbazides 3 or 1-heteroylthiocarbonyl semicarbazides 4, primarily formed by thioacylation of semicarbazide, where isolated. By cyclocondensation they yield 1,3,4-thiadiazole-2(3 H) ones 5, 6, or in the presence of acetic anhydride 3-acetyl-1,3,4-thiadiazol-2-ones- 7, 8, respectively.2-Amino- or 2-methylthio-1,3,4-thiadiazoles 11, 12 or 13, 14 are formed by reaction of the dithioesters 1, 2 with thiosemicarbazide or methyl dithiocarbazinate. By this way 1,3,4-thiadiazoles with heteroaryl- or carbamoylresidues in position 5 where synthesized for the first time.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19903320107
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    5-Aminothiazole aus Dithioestern und α-Aminoacetonitril (1990)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 332 (1990), S. 845-852 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 5-Aminothiazoles from Dithiocarboxylic Esters and α-AminoacetonitrileCarbamoyldithiocarboxylicesters 1 and heteroaryldithiocarboxylic esters 2 react with α-aminoacetonitriles under mild conditions to form 2-carbamoyl-5-aminothiazoles 5 or 2-heteroaryl-5-aminothiazoles 6. The intermediate N-cyanomethylthiooxamides 3 can be isolated. The 2-heteroaryl-5-aminothiazoles 6 and their acyl derivatives 7 are highly fluorescent, in contrast to the azomethines 8 derived from 6.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19903320604
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...