Time-resolved Raman studies on Al2 O3 : Cr3+ : lifetime measurements of the excited-state transition Ē → 2Ā

2010 ◽  
Vol 42 (5) ◽  
pp. 1109-1113 ◽  
Author(s):  
Yeny A. Tobon ◽  
Denis Bormann ◽  
Aurélien Canizares ◽  
Nicole Raimboux ◽  
Patrick Simon
1964 ◽  
Vol 42 (6) ◽  
pp. 1311-1323 ◽  
Author(s):  
M. A. Eswaran ◽  
C. Broude

Lifetime measurements have been made by the Doppler-shift attenuation method for the 1.98-, 3.63-, 3.92-, and 4.45-Mev states in O18 and the 1.28-, 3.34-, and 4.47-Mev states in Ne22, excited by the reactions Li7(C12, pγ)O18 and Li7(O16, pγ)Ne22. Branching ratios have also been measured. The results are tabulated.[Formula: see text]The decay of the 3.92-Mev state in O18 is 93.5% to the 1.98-Mev state and 6.5% to the ground state and of the 4.45-Mev state 74% to the 3.63-Mev state, 26% to the 1.98-Mev state, and less than 2% to the ground state. In Ne22, the ground-state transition from the 4.47-Mev state is less than 2% of the decay to the first excited state.


Author(s):  
M. RAVIKUMAR ◽  
R. P. PANDIAN ◽  
T. K. CHANDRASHEKAR

The singlet and triplet excited state properties of two diporphyrins, H 2- H and Zn - H , are described. Steady state fluorescence studies indicate that the emission of the H 2- H diporphyrin is dependent on the excitation wavelength and is dominated by the emission of the individual constituent monomers at their respective excitation. Time-resolved studies show two lifetimes ascribable to the normal and thiaporphyrin subunits. However, the emission of the Zn - H diporphyrin is dominated by the thiaporphyrin subunit irrespective of the wavelength of excitation, suggesting an energy transfer from the Zn porphyrin subunit to the thiaporphyrin subunit. Lifetime measurements in toluene show two lifetimes due to open and folded conformations, while in DMF an additional component due to axial ligation is observed. The efficiency of energy transfer is moderately higher in DMF (72%) than in toluene (68%). Triplet ESR studies on the H 2- H dimer reveal a localized triplet with ZFS parameters and ESP pattern the same as for the individual monomers. On the other hand, triplet ESR of the Zn - H diporphyrin reveals triplet characteristics of the thiaporphyrin subunit, indicating an energy transfer in the triplet state.


2019 ◽  
Author(s):  
Haoke Zhang ◽  
Lili Du ◽  
Lin Wang ◽  
Junkai Liu ◽  
Qing Wan ◽  
...  

<p>Building molecular machine has long been a dream of scientists as it is expected to revolutionize many aspects of technology and medicine. Implementing the solid-state molecular motion is the prerequisite for a practical molecular machine. However, few works on solid-state molecular motion have been reported and it is almost impossible to “see” the motion even if it happens. Here the light-driven molecular motion in solid state is discovered in two non-conjugated molecules <i>s</i>-DPE and <i>s</i>-DPE-TM, resulting in the formation of excited-state though-space complex (ESTSC). Meanwhile, the newly formed ESTSC generates an abnormal visible emission which is termed as clusteroluminescence. Notably, the original packing structure can recover from ESTSC when the light source is removed. These processes have been confirmed by time-resolved spectroscopy and quantum mechanics calculation. This work provides a new strategy to manipulate and “see” solid-state molecular motion and gains new insights into the mechanistic picture of clusteroluminescence.<br></p>


2019 ◽  
Vol 21 (7) ◽  
pp. 3606-3614 ◽  
Author(s):  
Maria Gabriella Chiariello ◽  
Umberto Raucci ◽  
Federico Coppola ◽  
Nadia Rega

We adopted excited state ab initio dynamics and a new time resolved vibrational analysis to unveil coupling between modes promoting photorelaxation.


RSC Advances ◽  
2021 ◽  
Author(s):  
Guanzhao Wen ◽  
Xianshao Zou ◽  
Rong Hu ◽  
Jun Peng ◽  
Zhifeng Chen ◽  
...  

Ground- and excited-states properties of N2200 have been studied by steady-state and time-resolved spectroscopies as well as time-dependent density functional theory calculations.


2011 ◽  
Vol 312 (9) ◽  
pp. 092062 ◽  
Author(s):  
V Werner ◽  
N Cooper ◽  
M Bonett-Matiz ◽  
E Williams ◽  
J-M Régis ◽  
...  

2009 ◽  
Vol 18 (02) ◽  
pp. 323-334 ◽  
Author(s):  
YURI A. LITVINOV

Mass and lifetime measurements of stored exotic nuclei is one of the successful experimental programs at the FRS-ESR facility of GSI, Darmstadt. Two experimental techniques, namely Isochronous and time-resolved Schottky mass spectrometry have been developed. Nuclides in a very broad range of half-lives starting from stable down to only a few ten microseconds can be addressed. Single stored ions can be measured which makes these techniques highly efficient. More than 1100 atomic masses have been measured meanwhile. Half-life measurements are performed with bare and few-electron ions. Decay properties of such highly-charged ions can be dramatically different from the ones known in neutral atoms. Single-particle decay spectroscopy has been developed for investigations of two-body beta decays. A brief description of the experimental methods and recent results will be presented. Future experiments at the present facility and the perspectives with the new NuSTAR/ILIMA project at FAIR will be outlined.


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