Energy dissipation in the ground-state vibrational manifolds ofβ-carotene homologues: A sub-20-fs time-resolved transient grating spectroscopic study

2008 ◽  
Vol 77 (20) ◽  
Author(s):  
Masazumi Fujiwara ◽  
Kensei Yamauchi ◽  
Mitsuru Sugisaki ◽  
Andrew Gall ◽  
Bruno Robert ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Spectroscopic Study ◽  
Ground State ◽  
Transient Grating ◽  
Time Resolved

scholarly journals Time-Resolved Spectroscopy of Q CYG

2004 ◽  
Vol 194 ◽  
pp. 237-237
Author(s):  
S. Kafka ◽  
C. Tappert ◽  
R. K. Honeycutt ◽  
A. Bianchini
Keyword(s):  
Spectroscopic Study ◽  
Ground State ◽  
Energy Levels ◽  
Low Density ◽  
Absorption Profile ◽  
Time Resolved ◽  
Long Period ◽  
Wind Event ◽  
Absorption Features ◽  
Different Parts

A time-resolved optical spectroscopic study of the long-period (P=10.08h) old nova Q Cyg has revealed persistent yet erratic absorption features indicating the presence of a wind, while the system was rising to one of its stunded outbursts. Data taken with the WIYN 3.5m telescope show P Cygni profiles in the He I triplet lines at 5876Å and 7065Å, which are absent in the He I singlet emission line at 6678Å, despite the fact that the relevant energy levels of those three lines are at very similar excitation levels. The Hα line often has a red ward emission tail, characteristic of a receding outflow, and it possess a blueward absorption profile during only one wind event. Kafka et al. (2003) argued that this behavior is due to the strongly metastable 2 3S effective ground state of the He I triplets, which becomes over-populated in conditions of low density and a dilute radiation field, over-populating in turn the 23P common lower level of He I 5876Å and 7065Å, leading to absorption from a low density wind. Therefore, the triplet/singlet lines trace two different parts of the system: the wind and the disk respectively.

scholarly journals Time-Resolved Investigation of the Molecular Chemiluminescence SrI(A2∏1/2,3,2,B2∑+→X2∑+) and the Atomic Resonance Fluorescence Sr(53P1→51S0) Following The Pulsed Dye Laser Generation Of Sr(53PJ) in the Presence of CF3I

1995 ◽  
Vol 16 (2) ◽  
pp. 121-138 ◽  
Author(s):  
S. Antrobus ◽  
D. Husain ◽  
Jie Lei ◽  
F. Castaño ◽  
M. N. Sanchez Rayo
Keyword(s):  
Ground State ◽  
Branching Ratio ◽  
Atomic Emission ◽  
Electronic Energy ◽  
Dye Laser ◽  
Pulsed Dye Laser ◽  
Laser Generation ◽  
Buffer Gas ◽  
Resonance Fluorescence ◽  
Time Resolved

A time-resolved investigation is presented of the electronic energy distribution in SrI following the collision of the optically metastable strontium atom, Sr [5s5p(3PJ)], with the molecule CF3I. Sr[5s5p(3PJ)], 1.807 eV above its 5s2(1S0) electronic ground state, was generated by pulsed dye-laser excitation of ground state strontium vapour to the Sr(53P1) state at , λ =689.3 nm {Sr(53P1←51S0)} at elevated temperature (840 K) in the presence of excess helium buffer gas in which rapid Boltzmann equilibration within the 53PJ spin-orbit manifold takes place. Time resolved atomic emission from Sr(53P1→51S0) at the resonance transition and the molecular chemiluminescence from SrI(A2∏1,2,3/2,B2∑+→X2∑+) resulting from reaction of the excited atom with CF3I were recorded and shown to be exponential in character. SrI in the A2∏1/2,3/2 (172.5, 175.4 kJ mol-1) and B2∑+ (177.3 kJ mol-1) states are energetically accessible on collision by direct-I-atomic abstraction between Sr(3P) and CF3I. The first-order decay coefficients for the atomic and molecular emissions are found to be equal under identical conditions and hence SrI(A2∏1/2,3/2, B2∑+) are shown to arise from direct I- atom abstraction reactions. The molecular systems recorded were SrI (A2∏1/2→X2∑+, Δv=0, λ=694 nm), SrI(A2∏3/2→X2∑+, Δv=0, λ=677 nm) and SrI(B2∑+→X2∑+) (Δv=0, λ=674 nm), dominated by the Δv=0 sequences on account of Franck-Condon considerations. The combination of integrated m61ecular and atomic intensity measurements yields estimates of the branching ratios into the specific electronic states, A1/2, A3/2 and B, arising from Sr(53PJ)+CF3I which are found to be as follows: A1/2,1.2 × 10-2; A3/2, 6.7 × 10-3; B, 5.1 × 10-3 yielding ∑SrI(A1/2+A3/2+B)=2.4 × 10-2. As only the X, A and B states SrI are accessible on reaction, assuming that the removal of Sr(53PJ) occurs totally by chemical removal, this yields an upper limit for the branching ratio into the ground state of ca. 98%. The present results are compared with previous time-resolved measurements on excited states of strontium halides that we have reported on various halogenated species resulting from reactions of Sr(53PJ), together with analogous chemiluminescence studies on Sr(3PJ) and Ca(43PJ) from molecular beam measurements.

A Time-Resolved Infrared Vibrational Spectroscopic Study of the Photo-Dynamics of Crystalline Materials

2009 ◽  
Vol 63 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Mike Towrie ◽  
Anthony W. Parker ◽  
Kate L. Ronayne ◽  
Katharine F. Bowes ◽  
Jacqueline M. Cole ◽  
...  
Keyword(s):  
Spectroscopic Study ◽  
Time Resolved ◽  
Crystalline Materials

Statistical Time-Resolved Spectroscopic Study on Upconversion Luminescence

2019 ◽  
Vol 124 (4) ◽  
pp. 2680-2688 ◽  
Author(s):  
Youngho Cho ◽  
Soo Yeong Lim ◽  
Song Yeul Lee ◽  
Jae Hun Kim ◽  
Yong Il Park ◽  
...  
Keyword(s):  
Spectroscopic Study ◽  
Upconversion Luminescence ◽  
Time Resolved ◽  
Statistical Time
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