In:
The Journal of Chemical Physics, AIP Publishing, Vol. 155, No. 15 ( 2021-10-21)
Abstract:
Ultraviolet (UV) and infrared (IR) spectra of protonated dopamine (DAH+) and its hydrated clusters DAH+(H2O)1–3 are measured by cryogenic ion spectroscopy. DAH+ monomer and hydrated clusters with up to two water molecules show a broad UV spectrum, while it turns to a sharp, well-resolved one for DAH+–(H2O)3. Excited state calculations of DAH+(H2O)3 reproduce these spectral features. The conformer-selected IR spectrum of DAH+(H2O)3 is measured by IR dip spectroscopy, and its structure is assigned with the help of quantum chemical calculations. The excited state lifetime of DAH+ is much shorter than 20 ps, the cross correlation of the ps lasers, revealing a fast relaxation dynamics. The minimal energy path along the NH → π proton transfer coordinate exhibits a low energy barrier in the monomer, while this path is blocked by the high energy barrier in DAH+(H2O)3. It is concluded that the excited state proton transfer in DAH+ is inhibited by water-insertion.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
2021
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
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