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Neutron Spin Echo Spectroscopy (NSE). Group B. Ilir Zoto Tao Hong Yanmei Lan Nikolaos Daniilidis Sonoko Kanai Mitra Yoonesi Zhaohui Sun 2003 Summer School NCNR, NIST Gaithersburg, MD 20890. NSE Time scale ~ 1 - 10 ns Size scale 1-100 Å. shape fluctuations. Spontaneous curvature,
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Neutron Spin Echo Spectroscopy(NSE) Group B Ilir Zoto Tao Hong Yanmei Lan Nikolaos Daniilidis Sonoko Kanai Mitra Yoonesi Zhaohui Sun 2003 Summer School NCNR, NIST Gaithersburg, MD 20890
NSE Time scale ~ 1 - 10 ns Size scale 1-100 Å shape fluctuations Spontaneous curvature, bending elasticity, Dynamics of particles k) Diffusion (T, h, r, R • NMR (Pulsed Field Gradient) s and higher • Dynamic light scattering s –ms, 1-100 nm
Surfactant molecule Hydrophilic head Hydrophobic tail Inverse spherical micelle D2O ~ 25 AOT AOT C10D22 C10D22 Experiment AOT Experiment I of AOT micelles in C10D22 (5.4 % vol. fraction) Experiment II AOT/D2O/C10D22 (5.4/4.6/90 % vol. fraction) Inverse microemulsion droplet
• elastic scattering • inelastic scattering 0 ± 0 <cos(±)> Angle ! B Principle of NSE L Neutrons posses spin and magnetic moment. They precess in magnetic fields with the Larmor frequency that depends on the strangth of the magnetic field only. (g =1.83108 s-1T-1) S N B B sample n
Experiment II AOT/D2O/C10D22 microemulsion Goal Experiment I AOT micelles in C10D22
Q Results
Å2/ns Å Results
Conclusion NSE is suitable for studies on: Diffusion of micelles/microemulsion Form Deformation http://dept.physics.upenn.edu/ ~pcn/mcgraw2/mcglatex.html
Acknowledgement Dobrin P. Bossev, Steve Kline, and Nicholas Rosov NCNR, NIST