Pico- and nanosecond time-resolved resonance Raman (TR3) spectroscopy have been utilized to study the dynamics and structure of p-hydroxyacetophenone (HA) and the p-hydroxyphenacyl-caged phototrigger compound p-hydroxyphenacyl diethyl phosphate (HPDP) in acetonitrile solution. Transient intermediates were detected and attributed to the triplet states of HA and HPDP. Nanosecond-TR3 measurements ...

We present a theoretical approach to investigate the electron spin polarization (ESP) of the excited triplet state that has been detected by using the time-resolved EPR (TREPR) method in the Photosystem II reaction center (PS II RC) of the plants. We show, by using the stochastic-Liouville equation, that the ESP pattern created in the accessory chlorophyll (ChlaccD1) which reside near the PD1 c...

Upconversion is the observation of high energy photon emission from low energy photon absorption. 1 Among the multiple upconversion mechanisms, one that has drawn recent interest is triplet-triplet annihilation (TTA). TTA holds significant advantages over its upconversion counterparts including its use of simple, tunable molecules and its ability to operate under low intensity, non-coherent lig...

To determine structure-optical property relationships in asymmetric platinum acetylide complexes, we synthesized the compounds trans-Pt(PBu3)2(C[triple bond]CC6H5)(C[triple bond]C-C6H4-C[triple bond]CC6H5) (PE1-2), trans-Pt(PBu3)2(C[triple bond]CC6H5)(C[triple bond]C-C6H4-C[triple bond]C-C6H4-C[triple bond]CC6H5) (PE1-3) and trans-Pt(PBu3)2(C[triple bond]C-C6H4-C[triple bond]CC6H5)(C[triple bon...

The double pump-probe technique (DPP), first introduced by Swatton et al. [Appl. Phys. Lett. 1997, 71, 10], is a variant of the standard pump-probe method but uses two pumps instead of one to create two sets of initial conditions for solving the rate equations, allowing a unique determination of singlet- and triplet-state absorption parameters and transition rates. We investigate the advantages...

Decays of individual rovibronic levels of trans-glyoxal in its first excited singlet state are investigated in supersonic-jet conditions. Several rotational levels display oscillatory decay from coherent excitation of superposition of singlet and triplet states. Analysis yields a lower bound for the state-dependent coupling matrix elements yST50.08– 62 MHz for the S1 – T1 interaction. These mat...

The triplet state of acridine orange dissolved in methanol/water matrix was investigated by ESR. In absence of oxygen a strong temperature dependence of the spectra was observed. At low temper­ ature (100 °K) the zero-field splitting parameters calculated from the triplet spectrum are: X /h c = 0.0050 cm-1 , Y / h c = 0.0342 cm-1 , Z //ic = 0.0387 cm-1 , at higher temperature (140 °K) : X * ( h...

Structure and bonding for a series of oxo-bridged and sulphur bridged alkali-metal centers (M-X-M: Li, Na and K; X = O, S) are studied for various M-X-M angles. The structures for these charge-transfer systems are compared with H-X-H. These chargetransfer systems show bonding and structures that are distinctively different from the covalent H-X-H molecules. The singlet-triplet gap for all of th...

The synthesis and photophysical characterization of a palladium(II) porphyrin - anthracene dyad bridged via short and conformationally rigid bicyclo[2.2.2]octadiene spacer were achieved. A spectroscopic investigation of the prepared molecule in solution has been undertaken to study electronic energy transfer in excited singlet and triplet states between the anthracene and porphyrin units. By us...