Ultrafast Relaxation Dynamics of [Au25(SR)18]q Nanoclusters: Effects of Charge State
The ultrafast electron relaxation dynamics of anionic and neutral Au{sub 25}(SR){sub 18} nanoclusters are investigated using broad-band time-resolved optical spectroscopy. From an analysis of the wavelength-dependent transient absorption kinetics, we have obtained valuable information on the spectral features that originate from excitation of 'core' and 'core-shell' states. In both clusters, photoexcitation occurs into two nondegenerate states near the HOMO-LUMO gap that are derived from the core orbitals. A large difference in the lifetime of the core excitations is observed, with [Au{sub 25}(SR){sub 18}]{sup -} exhibiting a decay rate more than 1000 times slower than the neutral cluster. Both clusters show strong coupling to two different coherent phonon modes, which are observed at 2.4 and 1.2 THz. The electron-phonon coupling is analyzed in terms of the spectral distribution and damping of the coherent modes.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
- Sponsoring Organization:
- DOE - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1000916
- Report Number(s):
- BNL-93921-2010-JA; ISSN 1932-7455; KC0202020; TRN: US1100241
- Journal Information:
- Journal of Physical Chemistry C, Vol. 114, Issue 47; ISSN 1932-7447
- Country of Publication:
- United States
- Language:
- English
Similar Records
Theoretical investigation of relaxation dynamics in the Au18 (SH)14 thiolate-protected gold nanocluster
Electronic relaxation dynamics in [Au25(SR)18]-1 (R = CH3, C2H5, C3H7, MPA, PET) thiolate-protected nanoclusters