10.6084/m9.figshare.1012387.v1 G M Nikolopoulos G M Nikolopoulos P Lambropoulos P Lambropoulos PSDs, bandwidths and coherence times, for fields with exponential and Gaussian correlations IOP Publishing 2013 decorrelation nature fel molecule framework Gaussian correlations interaction abstract psd role experiment coherence times fluctuation flash dynamic pulse bandwidth analysis regime decorrelated model Atomic Physics Molecular Physics 2013-08-13 00:00:00 Dataset https://iop.figshare.com/articles/dataset/_PSDs_bandwidths_and_coherence_times_for_fields_with_exponential_and_Gaussian_correlations/1012387 <p><b>Table 1.</b> PSDs, bandwidths and coherence times, for fields with exponential and Gaussian correlations.</p> <p><strong>Abstract</strong></p> <p>Motivated by recent experiments pertaining to the interaction of weak SASE-free-electron-laser (FEL) pulses with atoms and molecules, we investigate the conditions under which such interactions can be described in the framework of a simple phase-diffusion model with decorrelated atom–field dynamics. The nature of the fluctuations that are inevitably present in SASE-FEL pulses is shown to play a pivotal role in the success of the decorrelation. Our analysis is performed in connection with specific recent experimental results from FLASH in the soft x-ray regime.</p>