# Excited-State Chemistry of Hydroperoxymethyl Thioformate in the Troposphere

## TL;DR

This paper studies how a chemical formed from ocean emissions breaks down in sunlight, finding it degrades slowly and may not be a major atmospheric removal process.

## Contribution

The study reveals the photolytic pathway and efficiency of hydroperoxymethyl thioformate in the atmosphere, highlighting its limited role in removal.

## Key findings

- HPMTF photolysis has a high quantum yield (ϕ = 0.67) via S–C bond cleavage.
- HPMTF has a long photolytic lifetime (τ ≈ 30 h) due to weak UV–vis absorption.
- Photolysis is expected to be a minor sink for atmospheric HPMTF.

## Abstract

Dimethyl sulfide (DMS; CH3SCH3)
is a gas
produced by phytoplankton in the ocean and emitted into the atmosphere.
DMS emission is the largest source of atmospheric sulfur. Hydroperoxymethyl
thioformate (HPMTF) is an oxidation product of DMS in the marine atmosphere.
While the formation pathways of HPMTF are well established, the atmospheric
removal processes have yet to be fully characterized. Here, we study
the photochemistry of HPMTF using computational methods. Our results
indicate that HPMTF photolysis is efficient (high quantum yield, ϕ
= 0.67), primarily proceeding via S–C bond cleavage in the
thioformate (−SCHO) group. However, it is limited by the weak
absorption of UV–vis solar radiation, resulting in a long photolytic
lifetime (τ ≈ 30 h). Therefore, photolysis is expected
to represent a minor sink for atmospheric HPMTF.