scholarly journals Vibrational Energy Relaxation in the (d, d) Excited State Of Nickel Octaethylporphyrin

1999 ◽  
Vol 19 (1-4) ◽  
pp. 275-277 ◽  
Author(s):  
Yasuhisa Mizutani ◽  
Yuki Uesugi ◽  
Teizo Kitagawa
Keyword(s):  
Excited State ◽  
Vibrational Energy ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Energy Relaxation ◽  
Electronic Relaxation ◽  
Vibrational Energy Relaxation ◽  
Time Resolved ◽  
Time Regime ◽  
Anti Stokes

The formation of a hot photoproduct of nickel octaethylporphyrin (NiOEP) upon ππ* excitation and its subsequent vibrational energy relaxation were monitored by picosecond time-resolved resonance Raman spectroscopy. Resonance Raman bands due to the photoproduct instantaneously appeared upon the photoexcitation. Their intensities decayed with a time constant of 330±20ps, which indicates electronic relaxation form the (d, d) excited state (B1g) to the ground state (B1g). Anti-Stokes ν4 band of the hot (d, d) excited state of NiOEP appeared immediately after the excitation and decayed with time constants of 11±2 and 330±40 ps. In contrast, the rise of anti- Stokes ν7 intensity was not instantaneous but delayed by 2.6±0.5 ps, which suggests that IVR has not been completed in a subpicosecond time regime.

scholarly journals Time-Resolved Resonance Raman Spectroscopy of Excited-State Porphyrins

1999 ◽  
Vol 19 (1-4) ◽  
pp. 271-274 ◽  
Author(s):  
S. E. J. Bell ◽  
J. H. Rice ◽  
J. J. McGarvey ◽  
R. E. Hester ◽  
J. N. Moore ◽  
...  
Keyword(s):  
Excited State ◽  
Excited States ◽  
Laser Excitation ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Laser Pulses ◽  
Significant Shift ◽  
Time Resolved ◽  
Two Component ◽  
Absorbance Difference

Time-resolved resonance Raman (TR3) and absorbance difference studies of the excited states of Cu(TPP) (TPP=5,10,15,20-tetraphenylporphyrin) have been carried out with < 10 ps times resolution in THF and pyridine solvents. In THF the distinctive transient Raman bands in the ν2 and ν4 regions, previously observed with ns laser pulses, grow in the first 55 ps before decaying in 100's of ps. The ∆A spectra also show biphasic decay. This behaviour is associated with attack by solvent on the 4-coordinate excited state to form the longer lived species observed in TR3 experiments.In pyridine two component decay is also observed but it is the shorter-lived species which gives the transient Raman bands seen previously with ns laser excitation. This state is different from that seen in THF. At 5 ps delay ν4 is broader than in the ground state and, more importantly, there is a significant shift in the two pyridine bands at ca. 1000 cm-1. This implies a significant involvement of the pyridine-based orbitals in the excited state.

scholarly journals Determination of the Lowest Excited State of Metal Complexes of Dipyrido[3, 2-a:2′,3′-c]Phenazine

1999 ◽  
Vol 19 (1-4) ◽  
pp. 287-289
Author(s):  
Mark R. Waterland ◽  
Keith C. Gordon
Keyword(s):  
Raman Spectroscopy ◽  
Excited State ◽  
Metal Complexes ◽  
Excited States ◽  
Copper Complexes ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Time Resolved ◽  
State Data

The nature of the lowest excited state of rhenium and copper complexes of dipyrido[3,2- a:2′ ,3′-c]phenazine (Dppz) has been determined using Resonance Raman, Time- Resolved Resonance Raman Spectroscopy and Spectroelectrochemistry. Comparison of spectroelectrochemical data and excited state data show that for the complexes studied no reduced ligand bands are observed in the excited state spectra thus the lowest excited states are all Ligand Centred in nature. The use of substituents at the 11 and/or 12 position of the ligand has no effect on the excited state ordering.

Ligand-Specific Charge Localization in the MLCT Excited State of Ru(bpy)2(dpphen)2+ Monitored by Time-Resolved Resonance Raman Spectroscopy

1994 ◽  
Vol 33 (7) ◽  
pp. 1344-1347 ◽  
Author(s):  
Claudia Turro ◽  
Stefan H. Bossmann ◽  
George E. Leroi ◽  
Jacqueline K. Barton ◽  
Nicholas J. Turro
Keyword(s):  
Raman Spectroscopy ◽  
Excited State ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Specific Charge ◽  
Time Resolved ◽  
Charge Localization
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