korn_1998 ========= G\. Korn, O\. Duehr and A\. Nazarkin, "Observation of Raman Self\-Conversion of fs\-Pulse Frequency due to Impulsive Excitation of Molecular Vibrations", Phys\. Rev\. Lett\. 81, 1215 \(1998\) `Source record `__ · :doc:`Catalogue ` · :doc:`Review register ` DOI: `10\.1103/PhysRevLett\.81\.1215 `__ **Source kind:** measurement **Recorded technique:** Propagation of 40\-fs pulses at 400 nm \(frequency doubled, 300 uJ\) and 800 nm in a gas\-filled hollow waveguide \(250 um diameter, 72 cm, ~5 TW/cm2\) with SF6 at 0\.8\-1\.6 bar\: a pressure\-proportional red shift of the spectrum; pump\-probe \(20\-fs probe\) shows the 43\-fs period of the A1g vibration \(775 cm^\-1\); modelled with an electronic Kerr term plus a driven Raman oscillator \(pp\. 1215\-1217\)\. **Materials in structured entries:** None recorded. **Dataset quantities:** None recorded. **Contents:** 0 datasets; 0 formulas. Curation notes -------------- Journal pages 1215\-1218 = PDF pages 1\-4\. Identity checked against the first page\. SF6 only \(Ar is mentioned as a Kerr\-only reference, no value\)\. NO DATASET\: no n2 or hyperpolarizability is given\. TEXT \(notes only; no quantity for these\)\: the A1g Raman mode of SF6 at 775 cm^\-1, period T\_v = 43 fs \(pp\. 1215, 1217\); from the measured spectral shift 'we have estimated \(d alpha/dQ\) for the A1g mode of SF6\. For the 400\-nm\-excitation wavelength its value is 1\.5 x 10^\-16 cm2 in reasonable agreement with the available experimental data \[10\]' \(Weber, Raman Spectroscopy of Gases and Liquids\) and ~10 % of the molecules excited to v = 1 \(p\. 1218\)\. Model \(Gaussian\)\: P = P\_lin \+ P\_electr \+ P\_Raman, P\_Raman = N \(d alpha/dQ\) Q eps, Eq\. \(3\) d^2Q/dt^2 \+ \(2/T2\) dQ/dt \+ Omega\_v^2 Q = \(1/2M\)\(d alpha/dQ\) eps^2; Eq\. \(5b\) beta\_electr = 2 pi N omega chi\(3\)\_electr / cn, beta\_Raman = 4 pi^2 N omega \(d alpha/dQ\)^2 / \(M c^2 n^2\), I = \(cn / 8 pi\)\|E\|^2; Eq\. \(6\)\: the centre\-frequency shift d omega/dz = \-\(1/2\) beta\_Raman W, W the pulse energy per area \(pp\. 1217\-1218\)\. Bearing on optmat\: SF6's vibrational Raman response is impulsive for pulses shorter than ~40 fs and adiabatic \(part of the instantaneous Kerr response\) for longer ones\. **Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents. Datasets -------- No datasets are recorded. Formulas -------- No formulas are recorded. Corrections ----------- No dataset errata are recorded in this source record. Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the :doc:`review register ` for the checks and decisions.