The methylamine dimer, (CH₃NH₂)₂, is a model system to study the CH₃ and NH₂ spectral patterns in the neutral microsolvated systems relevant to chemical biology, atmospheric chemistry, and catalysis. We report infrared-vacuum ultraviolet spectroscopic measurements to probe the neutral (CH₃NH₂)₂. Quantum chemical calculations and ab initio molecular dynamics simulations were performed to understand the observed spectral features. Experimental and theoretical results indicate the likely coexistence of both cis and trans structures. A salient feature of this work is that the peak widths are not significantly affected by the structural transformation and the fluctuation of hydrogen bond distance, allowing the stretching modes to be clearly resolved.

中文翻译：

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中性甲胺二聚体的红外光谱和理论研究

甲胺二聚体（CH ₃ NH ₂）₂是研究与化学生物学，大气化学和催化有关的中性微溶剂化系统中CH ₃和NH ₂光谱模式的模型系统。我们报告红外真空紫外光谱测量以探测中性（CH ₃ NH ₂）₂。进行了量子化学计算和从头算分子动力学模拟，以了解观察到的光谱特征。实验和理论结果表明，顺式和反式结构可能共存。这项工作的一个显着特征是峰宽不受结构转变和氢键距离波动的显着影响，从而可以清楚地确定拉伸模式。