Electron‐electron double resonance of irradiated dimethylmalonic acid, α‐aminoisobutyric acid, and L‐alanine single crystals: The role of methyl substituents
Electron‐electron double resonance of irradiated dimethylmalonic acid, α‐aminoisobutyric acid, and L‐alanine single crystals: The role of methyl substituents
复制标题
辐照二甲基丙二酸、α-氨基异丁酸和L-丙氨酸单晶的电子-电子双共振：甲基取代基的作用
DOI：
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发表时间：
1973
期刊：
影响因子：
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通讯作者：
C. M. Bogan
中科院分区：
文献类型：
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作者：
L. Kispert;Kichoon Chang;C. M. Bogan
二甲基丙二酸和α-氨基异丁酸辐照单晶中的(CH3)2ĊCOOH自由基、辐照N,N-二氘代-α-氨基异丁酸单晶中的(CH3)2ĊCOOD自由基以及氘取代L-丙氨酸辐照单晶中的CH3ĊHCOOD自由基的电子-电子双共振(ELDOR)谱(CH3CHND2COOD) 在 170 至 370°K 的温度范围内测量。两种相互竞争的弛豫机制，即电子核偶极弛豫 (END) 和交叉弛豫机制，导致在 283°K 以上允许的 ESR 线观察到减少，并在 aH、2aH、3aH 和 4aH 处观察到 ELDOR 线。低于 283°K，ESR 线在 aH 处增强，在 2aH 处减少，并且在更高的 aH 倍数处 ELDOR 强度可以忽略不计。 (CH3)2·COOH 的 ELDOR 谱的温度依赖性的定性方面可以用分子内动态过程的相关时间来解释。基于这些机制的近似计算...
Electron‐electron double resonance (ELDOR) spectra of the (CH3)2ĊCOOH radical in irradiated single crystals of dimethylmalonic acid and α‐aminoisobutyric acid, the (CH3)2ĊCOOD radical in irradiated N,N‐dideutero‐α‐aminoisobutyric acid single crystals, and the CH3ĊHCOOD radical in irradiated single crystals of deuterium substituted L‐alanine (CH3CHND2COOD) were measured over a temperature range from 170 to 370°K. Two competing relaxation mechanisms, an electron‐nuclear dipole relaxation (END) and a cross relaxation mechanism, resulted in an observed reduction in the allowed ESR lines above 283°K with ELDOR lines observed at aH,2aH, 3aH, and 4aH. Below 283°K an enhancement of the ESR line occurred at aH, a reduction at 2aH and negligible ELDOR intensity at higher multiples of aH. The qualitative aspects of the temperature dependence of the ELDOR spectrum of (CH3)2ĊCOOH can be explained in terms of the correlation times of the intramolecular dynamic processes. Approximate calculations based on these mechanis...