Emergent Paramagnetism in D- and L-Alanine Crystals: Spin-Orbital Separation in Quasi-One-Dimensional N+H center dot center dot center dot O- Bonds

作者：Wang Wen Qing^*; Shen Xin Chun; Zhang Yu Feng; Gong Yan

来源：Acta Physico - Chimica Sinica, 2013, 29(7): 1396-1400.

DOI：10.3866/PKU.WHXB201304163

• D- and L-alanine crystal lattices
• N+H center dot center dot center dot O- hydrogen bond
• Emergent paramagnetism
• Electron spin-flip
• Electron spin-flop
• Energy difference of degenerate paramagnetic state
• Spin-orbital separation

We investigated the field-dependent magnetic properties of chiral alanine crystals, especially associated with the electronic orbital motions. Based on the chirality of the zwitterionic model (+NH3- C(CH3) H-CO2-) and the helicity of the lattice structure of peptide bond in proteins, when an external field of +5 T was applied parallel to the preferred axis c(z) of the N+H center dot center dot center dot O- hydrogen bond in D-alanine, the electron spin-flip manifested emergent paramagnetism at 297.6 K. Because the spin magnetic dipole moment of hydrogen in L-alanine was originally aligned antiparallel to the field, the electron spins flipped firstly perpendicular to the field then manifested paramagnetism at 303.9 K. The magnetic field of 5 T split a degenerate energy level in the paramagnetic state of chiral alanine. Furthermore, the spin-orbital separation of the quasi-one dimensional N+H center dot center dot center dot O- hydrogen bond in the crystal lattice provided evidence for the hallmark of one-dimensional physics.

• 出版日期2013-7
• 单位北京服装学院; 山东大学; 北京大学