140吉赫兹的脉冲电子-核双共振（ENDOR）

Pulsed electron-nuclear double resonance (ENDOR) at 140 GHz.

作者信息

Bennati M, Farrar C T, Bryant J A, Inati S J, Weis V, Gerfen G J, Riggs-Gelasco P, Stubbe J, Griffin R G

机构信息

Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

出版信息

J Magn Reson. 1999 Jun;138(2):232-43. doi: 10.1006/jmre.1999.1727.

DOI:10.1006/jmre.1999.1727

PMID:10341127

Abstract

We describe a spectrometer for pulsed ENDOR at 140 GHz, which is based on microwave IMPATT diode amplifiers and a probe consisting of a TE011 cavity with a high-quality resonance circuit for variable radiofrequency irradiation. For pulsed EPR we obtain an absolute sensitivity of 3x10(9) spins/Gauss at 20 K. The performance of the spectrometer is demonstrated with pulsed ENDOR spectra of a standard bis-diphenylene-phenyl-allyl (BDPA) doped into polystyrene and of the tyrosyl radical from E. coli ribonucleotide reductase (RNR). The EPR spectrum of the RNR tyrosyl radical displays substantial g-anisotropy at 5 T and is used to demonstrate orientation-selective Davies-ENDOR.

摘要

我们描述了一种用于140GHz脉冲电子核双共振（ENDOR）的光谱仪，它基于微波碰撞雪崩渡越时间（IMPATT）二极管放大器以及一个由TE011腔组成的探头，该腔带有用于可变射频辐照的高品质谐振电路。对于脉冲电子顺磁共振（EPR），我们在20K时获得了3×10⁹自旋/高斯的绝对灵敏度。通过将标准的双亚苯基 - 苯基 - 烯丙基（BDPA）掺杂到聚苯乙烯中以及大肠杆菌核糖核苷酸还原酶（RNR）的酪氨酸自由基的脉冲ENDOR光谱，展示了该光谱仪的性能。RNR酪氨酸自由基的EPR光谱在5T时显示出显著的g各向异性，并用于展示取向选择性戴维斯ENDOR。