ELECTRON-PARAMAGNETIC RESONANCE OF TM3+ IONS IN LANTHANIDE NICOTINATE DIHYDRATES
ELECTRON-PARAMAGNETIC RESONANCE OF TM3+ IONS IN LANTHANIDE NICOTINATE DIHYDRATES
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DOI：
10.1098/rspa.1986.0010
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发表时间：
1986-02-08
期刊：
影响因子：
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通讯作者：
MARTINEAU, PM
中科院分区：
文献类型：
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作者：
BAKER, JM;HUTCHISON, CA;MARTINEAU, PM
掺钙的二水烟酸镧(LAND)单晶在微波频率下的等电离辐射。0.01摩尔分数的Tm没有显示出孤立的Tm3+离子的光谱，但显示出最近邻的Tm3+离子对的光谱。自旋哈密顿参数与在纯TmNd中测量的自旋哈密顿参数大致相同；在稀薄材料中，169 Tm超精细结构被分解，并测量了每个Tm~(3+)离子基态双态的小零场分裂，用自旋哈密顿量项δSin来描述。对激发电磁场的条件和谱线的相对强度的仔细测量表明，跃迁是由塞曼算符的矩阵元素驱动的，涉及平行于矩阵主轴的微波磁场分量，只有当δ中有项时，这些分量才非零。结果表明，在纯TmND的δ中有一个类似的项，它对谱线位置的影响尚未解决，但它是产生观察到的跃迁强度所必需的。然而，这样的项将使∆ms=±1，∆mi=0跃迁在射频频率(15-30兆赫)下看不到，因为它将产生太大的能级之间的间隔；因此，它将使我们无法解释纯TmND在射频频率下的磁共振。需要进一步的实验才能理解纯TmND的跃迁机制。
E. p. r. at microwave frequencies in single crystals of lanthanum nicotinate dihydrate (LaND) doped withca. 0.01 mole fraction of thulium shows no spectrum of isolated Tm3+ions, but does exhibit spectra from coupled pairs of nearest-neighbour Tm3+ions. The spin hamilton parameters are approximately the same as those measured for such pairs in pure TmND; in the dilute material the169Tm hyperfine structure is resolved and a small zero-field splitting of the ground doublet of each Tm3+ion is measured, described by a term δSxin the spin hamiltonian. A careful measurement of the conditions for excitation of e. p. r., and of the relative intensities of the lines, indicates that the transitions are driven by matrix elements of the Zeeman operator, involving components of the microwave magnetic field parallel to the principal axis of thegmatrix, which are non-zero only if there is a term in δ. It is suggested that there is a similar term in δ in pure TmND, whose influence upon line positions is unresolved, but which is necessary to produce the observed transition intensity. However, such a term would render ∆MS= ±1, ∆mI= 0 transitions unobservable at r. f. frequencies (15-30 MHz) as it would produce too large a separation between the energy levels ; so it would leave us unable to account for the magnetic resonance at r. f. frequencies in pure TmND. Further experiments are required to produce an understanding of the transition mechanisms in pure TmND.