Fig. 3: PASADENA RASER of 4 demonstrates complex interplay of RASER-active frequencies.
From: Through-bond and through-space radiofrequency amplification by stimulated emission of radiation
a Reaction scheme of hydrogenation of 4' with p-H2 to produce HP 4. Red HA and HB atoms stand for parahydrogen-nascent atoms; protons labelled by yellow stars are RASER-active. RASER activity of 4c protons is induced via Nuclear Overhauser Effect (NOE). Colored arrows connect the pairs of protons between which the corresponding distances ζij in the spectrum (d) are presented. b 1H RASER signal acquired during PR-inside protocol experiment with 4'. The RASER signals are zoomed in vertical dimension so that 2% of all acquired RASER data points with extreme FID intensities are clipped; thus, the initial strong bursts are not visible fully but the dynamic of weaker signals is articulated. c Observed evolution of 1H NMR signals produced from RASER signal presented in panel (b). Frequency combs are marked by the arrows of corresponding colors. d 1H NMR spectrum produced by FT of RASER signal presented in panel (b); the spectrum is displayed as magnitude values and is zoomed to the baseline. Values ζij are ζac = 0.78 ppm (235 Hz), ζbc = 0.29 ppm (86 Hz), ζab = 1.07 ppm (320 Hz).
