Library

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
    Measurement of the hyperfine structure in low-l, high-n Rydberg states of ortho H2 by millimeter wave spectroscopy (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 113 (2000), S. 7939-7944 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Millimeter wave spectroscopy has been used to record high-resolution spectra of high-n (n=51–64), low-l (l=1–3) Rydberg states of ortho H2 located below the N+=1 rotational level of the X 2Σg+(v+=0) ground vibronic state of H2+. The spectral resolution of better than 1 MHz enables the observation of the hyperfine structure in these spectra. A simple procedure, based on the determination of combination differences, is used to reconstruct the energy level structure in np, nd, and nf Rydberg states of H2. The Stark effect is used to distinguish experimentally between p and f Rydberg states. In the weakly penetrating nf series, the hyperfine interaction dominates and the observed hyperfine components are of mixed singlet (S=0) and triplet (S=1) character. In the penetrating np series, the dominant interactions are between the electron orbital and spin angular momenta and the molecular rotation and the observed hyperfine components are characterized by a well-defined total electron spin. The nd Rydberg states show a behavior intermediate between these two limiting cases. The observed levels are of mixed singlet (S=0) and triplet (S=1) character but the main energy separation departs from the energy separation between the Gc=1/2 and Gc=3/2 levels of the H2+ ion. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1315608
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Selective field ionization of high Rydberg states: Application to zero-kinetic-energy photoelectron spectroscopy (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 115 (2001), S. 5461-5469 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Sequences of pulsed electric fields have been designed and tested that enable a higher selectivity in the pulsed field ionization of high Rydberg states (n≥100) than has so far been possible. The enhanced selectivity originates from the permutation of the parabolic quantum numbers n1 and n2 that is induced by a sufficiently rapid inversion of the electric field polarity during a pulse sequence. A reliable procedure, based on numerical simulations of the outcome of pulse field ionization sequences, has been developed to detect and control changes in the parabolic quantum numbers that can occur during a pulse sequence. The procedure can be used to assess under which conditions a clean permutation of the parabolic quantum numbers can be achieved. Unwanted randomization of m, n1 and n2, which reduces the selectivity of the field ionization process, can be avoided by minimizing the time intervals during which the electric field in the pulse sequence is almost zero. The high selectivity reached in the pulsed field ionization of high Rydberg states has been used to record pulsed-field-ionization zero-kinetic-energy photoelectron spectra of argon and nitrogen at an unprecedented resolution of 0.06 cm−1. This resolution opens new perspectives in photoelectron spectroscopy. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1396856
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Central Lumbar Disc Herniation (2000)
    Springer
    Acta neurochirurgica 142 (2000), S. 1369-1375 
    Details
    ISSN: 0942-0940
    Keywords: Keywords: Central; lumbar disc herniation; outcome; surgery.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary  A follow-up study which describes the experience of the Department of Neurosurgery in Berne in the treatment of patients with central lumbar disc herniation (CLDH).  Background Data. The anatomical position of lumbar disc herniation, in general, does not seem to affect postoperative outcome. However, according to other studies a subgroup of patients with central lumbar disc herniations appears to have poorer results.  Objectives. The aim of the present study was to assess clinical outcome in a recent cohort of patients, to investigate whether there is a difference in outcome with regard to the surgical approach (unilateral vs bilateral) and to compare the postoperative results between the subcategories of CLDH: central massprolaps (CMP) and central contained disc herniation (CCDH).  Methods. Between 1990 and 1997, 40 out of 3150 patients operated on for lumbar disc herniation were diagnosed with CLDH (1.2%). The patients were operated on through unilateral or bilateral fenestrations with microdiscectomy. Recent follow-up studies were obtained by standardized questionnaires. The retrospective investigation was performed by an unbiased observer.  Results. Long-term follow-up was available for 34 of the 40 patients (85%) at a mean of 3.3 years. Eight patients had an excellent result (24%), 15 patients a good result (44%), 8 patients a fair (24%) and 3 patients had a poor result (9%). Overall, the operation was considered successful in 68% of patients. There was no statistically significant difference in outcome in patients with CMP as compared with those with CCDH (75% versus 64%). There was also no significant difference for better outcome between bilateral as compared with unilateral approaches.  Conclusions. Postoperative outcome of central lumbar disc herniation (CLDH) is poorer as compared with other types of lumbar disc herniation. The reason seems to be the anatomical position of the disc herniation with a peculiar derangement of the disc architecture. The surgical approach itself or the subcategories of CLDH appear to have only minor impact on postoperative outcome. Interlaminar fenestrations, in general, are appropriate for removal of the disc fragments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007010070007
    Library Location Call Number Volume/Issue/Year 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...