title: Origin of anomalous spectra of dynamic alignments observed in N2 and O2.
abstract: Recent pump-probe experiments with intense femtosecond laser pulses and diatomic molecules N2 and O2, have revealed the presence of Raman-forbidden anomalous series and lines in the Fourier spectrum of HHG (high harmonic generation) signals. A theoretical analysis of the problem is made by deriving a general expression of the angle dependent HHG operator that governs the dynamic alignment signals in linear molecules, and applying them to the experiments in N2 and O2. A unified interpretation of the origin of the observed Raman-allowed and the anomalous spectral features is given. The results are also used to estimate the molecular temperature in the experiments.
authors.affiliation: Fakultät für Physik, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany.
authors.forename: F H M
authors.initials: FH
authors.lastname: Faisal
authors.forename: A
authors.initials: A
authors.lastname: Abdurrouf
authors.forename: K
authors.initials: K
authors.lastname: Miyazaki
authors.forename: G
authors.initials: G
authors.lastname: Miyaji