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
    Laser induced fluorescence spectra of the D 1∑u+→B′ 1∑g+ and C 1Πg→A 1∏u systems of C2 in solid Ne (2002)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 116 (2002), S. 5996-6001 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In our study of carbon vapor molecules trapped in Ne matrices at 6 K, we observed laser induced fluorescence spectra of the D 1∑u+→B′ 1∑g+ system of C2 upon excitation of the Mulliken transition D 1∑u+←X 1∑g+ of C2 at 232 nm. A vibrational progression was clearly observed going from the upper vibrational v′=0 level of the electronic D state into several lower v″=0–6 levels of the B′ state. We found that the progression spans from 359 to 517 nm with a large Franck–Condon shift showing the intensity maximum for the 0–2 or 0–3 transition. The vibrational constants for the B′ state were derived as ωe=1427 cm−1 and ωexe=2.1 cm−1. We also observed the C→A and the Swan band emissions, showing that from the excited D state also additional states were populated by internal conversion and intersystem crossing. The constants for the A state were derived as ωe=1613.5 cm−1 and ωexe=18.5 cm−1. Fluorescence excitation spectra of the D→B′ vibronic transitions were found to reproduce well the relatively narrow absorption feature of the Mulliken D←X system. We discuss the entirely different excitation spectra occurring in argon matrices in terms of matrix-site effects. Each vibronic band of the D→B′ progression shows fine structures probably due to translations and librations of C2 molecules coupled with the surrounding lattice of Ne atoms. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1457437
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Mass spectroscopic studies of laser ablated carbon clusters as studied by photoionization with 10.5 eV photons under high vacuum (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 111 (1999), S. 6260-6263 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Neutral carbon clusters Cn (n=1–30) produced along with ionic clusters in laser vaporized graphite are studied under high vacuum by combined use of time-of-flight (TOF) mass spectroscopy and one photon ionization with a photon energy of 10.5 eV. The TOF mass distribution pattern shows intensification of the C4n+2 (n≥2) clusters more clearly than the previous work by Kaizu et al. [J. Chem. Phys. 106, 9954 (1997)] who employed the same 10.5 eV photon but photoionized the neutral clusters generated by laser vaporization of graphite in helium buffer gas. The intensification is attributed to the intrinsic stability of the C4n+2 (n≥2) neutral clusters, probably due to the monocyclicity. Two different line shapes of the mass spectral peak are observed for one and the same cluster size. The line shape with a tailing toward longer flight times is associated with the neutral clusters produced by relatively slow fragmentation of larger clusters (n(very-much-greater-than)30) followed by autoionization of the fragmented clusters. The other sharp line shape is associated with prompt ionization by the 10.5 eV photon. It is concluded that only the electronically excited neutral clusters are ionized for n≤5 whereas the clusters with n〉5 are ionized irrespective of their electronic state. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.479931
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Photoinduced reactions of methyl radical in solid parahydrogen (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 6346-6350 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Photolysis of methyl iodide in solid parahydrogen (p-H2) at about 5 K is studied with ultraviolet light at 253.7 and 184.9 nm. It is found that the light at 253.7 nm produces only methyl radical, whereas the light at 184.9 nm yields both methyl radical and methane. The mechanism of the formation of the photoproducts is elucidated by analyzing the temporal behavior of the observed vibrational absorption. It is concluded that methyl radical in the ground state does not react with p-H2 molecules appreciably but that the radical in the electronic excited state of B˜(2A1′), accessible by reabsorption of 184.9 nm photons by the radical, decomposes to a singlet methylene CH2 a˜(1A1) and a hydrogen atom (2S) and that the singlet methylene reacts with a p-H2 molecule to give methane. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.477276
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Preferential formation of C10− upon tandem irradiation of graphite with IR and UV laser pulses (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 107 (1997), S. 1152-1155 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Infrared (IR) pulse laser ablation of graphite followed by tightly focused ultraviolet (UV) pulse laser irradiation yields C10− predominantly when the delay time between the two laser pulses is set at about 50–200 μs. The mechanism of the formation of C10− is deduced to be the attachment of slow photoelectrons to neutral C10 produced by fragmentation of hot neutral clusters of larger sizes. There is an indication that C10 and its anion have cyclic structures in contrast to the other chainlike clusters. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.474461
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Infrared spectroscopic study of rovibrational states of perdeuterated methane (CD4) trapped in parahydrogen crystal (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 5728-5733 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The triply degenerate stretching (ν3) and bending (ν4) modes of CD4 in solid parahydrogen at cryogenic temperatures are studied by Fourier transform infrared spectroscopy to reveal crystal field split rovibrational structures. The observed spectra are analyzed by taking into account the crystal field potential which is constructed by the summation of the pairwise (dispersive) potential between the methane and the surrounding hydrogen molecules. By the least-squares fitting of that observed to a theoretical model the molecular constants of CD4 as well as the potential coefficient are determined as in the previous work on the CH4/p-H2 system. The potential is approximated to be proportional to the product of the polarizability of hydrogen molecule, the dipole–quadrupole polarizability of methane, and the inverse of the seventh power of the intermolecular distance between methane and hydrogen molecules. From the ratio of the potential coefficients of CH4 and CD4 the dipole–quadrupole polarizability of CD4 is found to be 0.875 times that of CH4 under the assumption that the quantum renormalization effect is negligible. A novel temperature dependence of the line shape of the ν3 and ν4 modes is discovered over the range of 4.5 to 8.0 K. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.478471
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    High-resolution laser spectroscopy of methane clusters trapped in solid parahydrogen (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 107 (1997), S. 7717-7720 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Clusters of methane are isolated in solid parahydrogen. The vibrational spectral region of the ν4 fundamental of methane molecule is surveyed with a Fourier transform infrared spectrometer and a high-resolution difference-frequency infrared laser system. More than 200 sharp absorption lines are discovered whose linewidth is as narrow as 0.007 cm−1 (200 MHz). The spectrum indicates that the rovibrational levels of the clusters of small sizes are well quantized in solid parahydrogen. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.475086
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Infrared spectroscopic study of rovibrational states of methane trapped in parahydrogen crystal (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 107 (1997), S. 7707-7716 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The ν3 and ν4 vibrational transitions of methane trapped in solid parahydrogen have been observed by using Fourier transform infrared and high resolution laser spectroscopy. The observed spectrum is interpreted in terms of rovibrational states of the spherical rotor which are subjected to the crystal field splitting. The ν4 band shows extremely sharp lines of a width of ∼0.003 cm−1, while the ν3 band exhibits broader lines of a width of 1 cm−1. The infrared selection rules derived from an extended group theory to take into account the field effect are consistent with the observed spectra. The intermolecular interaction and the field effect in solid parahydrogen are analyzed quantitatively. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.475085
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Photoelectron spectroscopy of Cn− produced from laser ablated dehydroannulene derivatives having carbon ring size of n=12, 16, 18, 20, and 24 (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 107 (1997), S. 4783-4787 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: n-Dehydroannulenes with the ring size of n=12, 16, 18, 20, and 24 and with three to five indanyl substituents are laser ablated by 355 nm photons. The indanyl unit is lost stepwise up to the complete deletion to leave the bare annulenyl skeleton. The monoanions of these products are mass analyzed first, and then subjected to a second laser pulse of 266 nm to obtain photoelectron spectra for Cn− with n=12, 16, 18, 20, and 24. The spectra are compared with those obtained by using graphite as a target of the laser ablation. The comparison of the two spectra provides useful information on the structure of neutral carbon clusters. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.474841
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Tunneling chemical reactions in solid parahydrogen: A case of CD3+H2→CD3H+H at 5 K (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 108 (1998), S. 7334-7338 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Ultraviolet photolysis of CD3I in solid parahydrogen at 5 K gives CD3 radical, which decreases in a single exponential manner with a rate constant of (4.7±0.5)×10−6 s−1. Concomitantly, CD3H is formed, which is accounted for by the quantum tunneling reaction CD3+H2→CD3H+H. Under the same conditions, CH3I yields CH3 radical, but the corresponding reaction between CH3 and H2, expected to give CH4+H, does not proceed measurably at 5 K. The difference between the two systems is attributed to the difference in the zero point energy change. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.476152
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    NMR characterization of isomers of C 78 , C 82 and C 84 fullerenes (1992)
    [s.l.] : Nature Publishing Group
    Nature 357 (1992), S. 142-145 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We isolated C7g, C82 and C84 by high-performance liquid chromatography (the preparation is described in detail elsewhere4'5). Laser-desorption time-of-flight mass spectra were obtained to confirm the purity of the isolated samples. We used an ArF (193 nm) laser as the desorption light source5. ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/357142a0
    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...