The triplet excited states of sulfur dioxide can be accessed in the UV region and have a lifetime large enough that they can react with atmospheric trace gases. In this work, we report high level ab initio calculations for the reaction of the a³B₁ and b³A₂ excited states of SO₂ with weak and strong acidic species such as HCOOH and HNO₃, aimed to extend the chemistry reported in previous studies with nonacidic H atoms (water and alkanes). The reactions investigated in this work are very versatile and follow different kinds of mechanisms, namely, proton-coupled electron transfer (pcet) and conventional hydrogen atom transfer (hat) mechanisms. The study provides new insights into a general and very important class of excited-state-promoted reactions, opening up interesting chemical perspectives for technological applications of photoinduced H-transfer reactions. It also reveals that atmospheric triplet chemistry is more significant than previously thought.

中文翻译：

---

三重态自由基化学：3SO2 与 HCOOH 和 HNO3 反应的意义


二氧化硫的三重激发态可以在紫外区域获得，并且具有足够长的寿命，可以与大气中的痕量气体发生反应。在这项工作中，我们报告了 a ³ B ₁ 和 b ³ A ₂ 激发反应的高级从头计算SO ₂ 与弱酸性和强酸性物质（例如 HCOOH 和 HNO ₃ ）的状态，旨在扩展先前研究中报道的非酸性 H 原子（水和烷烃）的化学反应。这项工作中研究的反应非常通用，并且遵循不同类型的机制，即质子耦合电子转移（pcet）和传统的氢原子转移（hat）机制。这项研究为一类普遍且非常重要的激发态促进反应提供了新的见解，为光诱导氢转移反应的技术应用开辟了有趣的化学前景。它还揭示了大气三重态化学比之前想象的更重要。