{
  "annotation_id": "31ec1993-3100-42fd-8143-9321970f87b5",
  "date_created": "2026-02-17T05:53:04.194000Z",
  "date_modified": "2026-02-17T05:53:04.194000Z",
  "file_hash": "18fd22906d6cadafecbaab7479fbcc3679bdf1e8b7d291603140db26f9b30d69",
  "private": false,
  "record": {
    "abstract": "Verdazyl radicals are a versatile class of air-stable organic radicals used in various applications, especially for their magnetic properties. Despite the development of a wide range of verdazyl derivatives, however, they are all non-emissive. To investigate the reasons behind this and to understand the excited-state dynamics of verdazyls, we combine steady-state and femtosecond pump-probe spectroscopy with quantum chemical calculations. In the carbazole-substituted 2,4,6-triphenylverdazyl (TPV-Cz) , we observe ultrafast internal conversion of the first excited state on a timescale of 0.5 $\\pm$ 0.1 ps, followed by vibrational relaxation with a lifetime of 3.7 $\\pm$ 0.4 ps. Spin-flip time-dependent density functional theory calculations reveal that the sub-picosecond non-radiative decay comes from a low-energy conical intersection between the D1 and D0 states, driven by an out-of-plane distortion of the verdazyl ring. This distortion is observed and remains energetically accessible in the isolated verdazyl ring in 2,4,6-triphenylverdazyl and in TPV-Cz. This shows that the conical intersection geometry is a recurring feature across different types of verdazyl derivatives and explains why all verdazyls are non-emissive despite different functionalization. Our results provide a mechanistic understanding of the photophysical properties of verdazyl radicals and offers a pathway for the future design of emissive verdazyl derivatives.",
    "arxiv_id": "2601.05390",
    "authors": [
      "Alexandre Malinge",
      "Pierre-Luc Th\u00e9riault",
      "St\u00e9phane K\u00e9na-Cohen"
    ],
    "categories": [
      "physics.chem-ph"
    ],
    "license": "http://creativecommons.org/licenses/by/4.0/",
    "title": "Why Are Verdazyl Radicals Non-Emissive? An Experimental and Computational Study",
    "url": "https://arxiv.org/abs/2601.05390",
    "version": "v1"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "bbe95336-20bb-4766-a17b-d6d5577af187",
    "id": "arXiv Dataset",
    "type": "Model",
    "variant": "snapshot-2026-01-17",
    "version": "0.1.0"
  },
  "user_id": 1000002
}