A new six-pulse two-dimensional electron spin echo envelope modulation (ESEEM) correlation spectroscopy

Sensitivity Enhancement by Matched Microwave Pulses in One- and Two-Dimensional Electron Spin Echo Envelope Modulation Spectroscopy

“…In schemes for enhancing weak echo modulations by using particular, it is shown that in HYSCORE experiments the signal-building blocks better suited to the generation of nuclear to-noise ratio improvement for strongly coupled nitrogens and for coherence (11)(12)(13)(14). A particularly promising approach proton combination peaks may be considerably larger than one makes use of matched or high-turning-angle (HTA) mw order of magnitude, corresponding to a reduction in measuring pulses for optimizing the generation and transfer of cohertime of more than a factor of 100.…”

Line-shifting method in electron spin echo envelope modulation (ESEEM) studies

“…1) [5]. Al1 experiments were performed on an X-band (9-10 GHz) pulsed EPR spectrometer (Bruker ESP380E).…”

“…The other BF-ESEEM spectrum was measured with (AtŸ = (At~)BF = 16 ns, and thus the same increments are used in both the BF-and MIF-ESEEM experiments in this case. A four-step phasecycling scheme for the six-pulse ESEEM measurements [5] was adopted to suppress unwanted spin echoes.…”

“…A four-pulse sequence (a), a six-pulse scheme (6). t~ = ti0 + t; + ~,t~ , t2 = t2o + 7t; + t~ , (5) where Z= At2/At 1 while t i is kept constant, or ~,= Atl/At 2 while tŸ is fixed, and At~ and At 2 are the time increments of t I and t2, respectively, tLo and t20 are initial values for t I and tE, respeetively, to ensure t 1 and t 2 are always greater than zero. To be more specific, in the expe¡ (1 + Zl)tŸ is acquired as one dimension, and (1 + 2z2)t~ is used as the other.…”

“…The three-pulse stimulated echo sequence was developed into a four-pulse two-dimensional (2D) ESEEM experiment [4], named HYSCORE (hyperfine sublevel correlation) spectroscopy, by inserting a mixing n pulse between the second and third n/2 pulses. Recently the original four-pulse 2D ESEEM scheme has been improved with a six-pulse 2D ESEEM experiment to increase cross peaks and suppress diagonal peaks, by tucking in a mixing r~ pulse between the third and fourth pulses in the five-pulse sequence [5]. In all of those ESEEM experiments, the emphasis is on the basic nuclear transition frequencies w a and wp.…”