ABSTRACT Formation and growth of atmospheric aerosols are governed by the Gibbs energy of complex formation (). A number of hydrogen bound bimolecular complexes in the gas phase at room temperature have been detected. In this review, we illustrate how can be determined by combining gas phase infrared spectroscopy and vibrational theory. The XH-stretching (where X is a heavy atom like O) fundamental transition of the hydrogen bond donor molecule in the complex is redshifted and its intensity enhanced upon complexation. This facilitates detection of weak complexes even though the equilibrium is shifted towards the monomers at room temperature. The ratio of the measured and calculated intensity of the vibrational transition is proportional to the complex abundance, which with known monomer pressures gives the equilibrium constant and thus . This approach relies on calculated vibrational transitions in the complexes. An accurate description of the observed bound XH-stretching fundamental transition is challenging due to effects of the low-frequency intermolecular modes. We have developed reduced dimensionality vibrational models within the local mode picture to calculate accurate vibrational intensities. For complexes with an alcohol donor molecule, we find that P, O or S as the acceptor atom of the hydrogen bond results in very similar hydrogen bond strength, whereas N provides a significantly stronger bond.

中文翻译：

---

复合物的吉布斯能量——结合红外光谱和振动理论

摘要 大气气溶胶的形成和生长受复合物形成的吉布斯能（ ）控制。已在室温下在气相中检测到许多与氢结合的双分子复合物。在这篇综述中，我们说明了如何通过结合气相红外光谱和振动理论来确定。复合物中氢键供体分子的 XH 拉伸（其中 X 是像 O 一样的重原子）基本跃迁发生红移，复合后其强度增强。这有助于检测弱复合物，即使平衡在室温下向单体移动。振动跃迁的测量和计算强度的比率与复数丰度成正比，在已知单体压力下，它给出了平衡常数，因此 。这种方法依赖于复合物中计算出的振动转变。由于低频分子间模式的影响，对观察到的结合 XH 拉伸基本跃迁的准确描述具有挑战性。我们在局部模式图片中开发了降维振动模型来计算准确的振动强度。对于具有醇供体分子的复合物，我们发现 P、O 或 S 作为氢键的受体原子导致非常相似的氢键强度，而 N 提供了明显更强的键。我们在局部模式图片中开发了降维振动模型来计算准确的振动强度。对于具有醇供体分子的复合物，我们发现 P、O 或 S 作为氢键的受体原子导致非常相似的氢键强度，而 N 提供了明显更强的键。我们在局部模式图片中开发了降维振动模型来计算准确的振动强度。对于具有醇供体分子的复合物，我们发现 P、O 或 S 作为氢键的受体原子导致非常相似的氢键强度，而 N 提供了明显更强的键。