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Greetham, Gregory M.
Preferred name
Greetham, Gregory M.
Official Name
Greetham, Gregory M.
Research Output
Now showing 1 - 4 of 4
- PublicationUltra Laser Facility Applications for Chemistry, Life Sciences and Catalysis(2016-09-30)
; ; ; ; We describe ULTRA laser facility applications for chemistry, life sciences and catalysis, illustrated by vibrational control of electron transfer; photoinduced electron transfer in DNA crystals; and operando Kerr-gated Raman insight into catalytic hydrocarbon conversion with zeolites50 - PublicationPhotophysical studies of CdTe quantum dots in the presence of a zinc cationic porphyrin(RSC Publishing, 2012-09-24)
; ; ; ; ; ; ; ; ; The photophysical properties of 2.3 nm thioglycolic acid (TGA) coated CdTe quantum dots (QDs) prepared by a reflux method have been studied in the presence of cationic meso-tetrakis(4-N-methylpyridyl) zinc porphyrin (ZnTMPyP4). Addition of the CdTe QDs to the porphyrin in H2O results in a marked red-shift and hypochromism in the porphyrin absorption spectrum, indicative of a non-covalent binding interaction with the QD surface. Only low equivalents of the quantum dot were required for complete quenching of the porphyrin fluorescence revealing that one quantum dot may quench more than one porphyrin. Similarly addition of porphyrin to the quantum dot provided evidence for very efficient quenching of the CdTe photoluminescence, suggesting the formation of CdTe'porphyrin aggregates. Definitive evidence for such aggregates was gathered using small angle X-ray spectroscopy (SAXS). Ultrafast transient absorption data are consistent with very rapid photoinduced electron transfer (1.3 ps) and the resultant formation of a long-lived porphyrin species.450Scopus© Citations 25 - PublicationA comparative picosecond transient infrared study of 1-methylcytosine and 5'-dCMP that sheds further light on the excited states of cytosine derivatives(ACS Publications, 2011-03)
; ; ; ; ; ; ; ; ; The role of N1-substitution in controlling the deactivation processes in photoexcited cytosine derivatives has been explored using picosecond time-resolved IR spectroscopy. The simplest N1-substituted derivative, 1-methylcytosine, exhibits relaxation dynamics similar to the cytosine nucleobase and distinct from the biologically relevant nucleotide and nucleoside analogues, which have longer-lived excited-state intermediates. It is suggested that this is the case because the sugar group either facilitates access to the long-lived (1)n(O)Ï * state or retards its crossover to the ground state.418Scopus© Citations 40 - PublicationUltrafast IR spectroscopy of polymeric cytosine nucleic acids reveal the long-lived species is due to a localised state(RSC Publishing, 2012-02-22)
; ; ; ; ; ; ; ; ; The decay pathways of UV-excited cytosine polymers are investigated using picosecond time-resolved infrared spectroscopy. Similar yields of a non-emissive (1)nÏ * state are found in the single-stranded dC(30) polymer as in the dCMP monomer, but with a longer lifetime in the polymer (80 ps vs. 39 ps). A longer lifetime is also found in the d(CpC) dinucleotide. No evidence of excimer states is observed, suggesting that localised (1)nÏ * excited states are the most significant intermediates present on the picosecond timescale.334Scopus© Citations 11