Non-uniform sampling in pulse dipolar spectroscopy by EPR: the redistribution of noise and the optimization of data acquisition

Abstract

Non-uniform schemes for collection of pulse dipole spectroscopy data can decrease and redistribute noise in the distance spectrum for increased sensitivity and throughput.

Confidence limits in pulse dipolar EPR spectroscopy: estimates for individual measurements

“…Relative widths of δ r 0 / r 0 = 0.03, 0.05, 0.1, 0.15, and 0.2 generated datasets that are readily extensible to any unimodal Gaussian distribution. 19 Other realistic distributions would complicate rather than clarify this study, e.g. , a simple bimodal Gaussian distribution has five, strongly correlated degrees of freedom.…”

“…The sampling step d t was chosen to provide an experimental “open window” nominally between 0.5· r 0 and 1.3· r 0 . 19 Within this open window, truncation and sampling noise 19 have little impact on the distance spectrum recovered from the noiseless dipolar trace by the model-free approaches utilizing Tikhonov regularization or the Mellin transform, see ESI,† Section S1.…”

“…Results are presented in terms of relative distance, time, and frequency, exploiting the scaling properties of PDS 19 to show their broad applicability. Datasets were generated with the nominal r 0 = 3.96 nm, i.e.…”

“…They apply broadly to most PELDOR/DEER experiments, and are not restricted to a specific DDF because time, distance and dipolar frequency have consistent scaling relationships in PDS. 19…”

A Peptide-Based Trap for Metal Ions Studied by Electron Paramagnetic Resonance

“…The time delay τ was set to 1000 ns, the sequence repetition time was kept at 1 ms, providing more than 90% of echo intensity. The minimal reliable r min value was limited by the sampling frequency [53] and by the amplitude of the pumping pulse [54] to 1.57 nm under the chosen experimental conditions. The phase jumps due to the passage of the pumping pulse through the first detection pulse were eliminated by the measuring scheme described by Milov [55].…”