ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Excited-state proton transfer dynamics are reported for the 1-naphthol(NH3)n cluster system for n=3 and 4. Picosecond time- and mass-resolved pump (S1←S0)–probe (I←S1) experiments demonstrate the following results: (1) excited-state proton transfer occurs for n=3 and 4 clusters only; (2) for n=5 clusters the proton is transferred in the ground state and for n=2 clusters no proton transfer can be observed; (3) the proton transfer time in the n=3 cluster at the 000 transition is ca. 60 ps; (4) this time is reduced to ca. 40 ps and ca. 10 ps for 800 and 1400 cm−1 of vibrational energy in S1, respectively; (5) for the n=4 clusters these times are approximately 70, 70, and 30 ps, for 0, 800, and 1400 cm−1 of vibrational energy in S1, respectively; (6) both n=3 and 4 clusters exhibit a second low-amplitude decay component, which is about an order of magnitude slower than the initial decay; and (7) 1-naphthol-d1(ND3)n clusters have a greatly reduced rate constant for the excited-state proton transfer dynamics. These observations are well fit and explained by a simple statistical/barrier penetration model involving proton tunneling and the effect of van der Waals vibrations on the height and width of the barrier to proton transfer.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.462971
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