Photophysics of simple saturated amines

The role of novel Rydberg-valence behaviour in the non-adiabatic dynamics of tertiary aliphatic amines

“…As discussed previously, radiative decay via fluorescence has been suggested as a possible pathway, 13 although it seems unlikely this is the dominant relaxation mechanism (following 200 nm excitation) on the basis of quantum yield data reported for several other TAA systems. 14 – 16 It is also difficult to see how fluorescence decay leads to increased β 2 and β 4 values at long pump–probe delay times (see Fig. 7 ) as this process does not directly couple the initial and final electronic states.…”

“…However, quantum yield studies in several other amine systems suggest that non-radiative relaxation becomes dominant at excitation wavelengths <220 nm (5.6 eV). 14 – 16 Of particular note here is a fluorescence lifetime study by Phillips and co-workers, 15 who reported dual exponential decay in several TAA systems following excitation at energies sufficient to populate the 3s state and 3p manifold simultaneously. This was rationalized by suggesting internal conversion and direct excitation produce different vibrational distributions in the 3s state, leading to the former process having an enhanced propensity for non-radiative decay.…”

The effects of symmetry and rigidity on non-adiabatic dynamics in tertiary amines: a time-resolved photoelectron velocity-map imaging study of the cage-amine ABCO

“…Fluorescence is the most likely option, but despite fluorescence lifetimes of more than 300 ns being reported at excitation wavelengths of both 236 and 249 nm, 9 a dramatic drop in both quantum yield and fluorescence lifetime at lower excitation wavelengths would be expected, similar to what has been found for a range of smaller tertiary amines. [44][45][46] An early multiphoton ionization study of ABCO has also shown the existence of a fast non-radiative decay channel for the Rydberg states. 6 In our previous TRPEI study of other TAAs, an observed rise in the b parameters at long pump-probe delay times was an important indicator in ruling out fluorescence decay.…”

Spectroscopic application of few-femtosecond deep-ultraviolet laser pulses from resonant dispersive wave emission in a hollow capillary fibre

“…This is particularly true given a study of the related N,N-dimethylisopropylamine system has revealed lifetimes extending to over a nanosecond towards the red end of the 3s absorption band. 59 We note, however, that quantum yield studies in several other tertiary amine systems suggest uorescence is an important decay pathway at excitation wavelengths >220 nm, [60][61][62][63] while nonradiative energy redistribution pathways become predominant following higher energy absorption. Of particular relevance here is a uorescence lifetime study reporting dual exponential decay in several amine systems following measurements that excite the 3s state and 3p manifold simultaneously.…”