scholarly journals Vibrational energy relaxation of benzene dimer and trimer in the CH stretching region studied by picosecond time-resolved IR-UV pump-probe spectroscopy

2012 ◽  
Vol 136 (4) ◽  
pp. 044304 ◽  
Author(s):  
Ryoji Kusaka ◽  
Yoshiya Inokuchi ◽  
Takayuki Ebata
Keyword(s):  
Vibrational Energy ◽  
Energy Relaxation ◽  
Vibrational Energy Relaxation ◽  
Time Resolved ◽  
Pump Probe ◽  
Benzene Dimer ◽  
Probe Spectroscopy

Real time observation of the excimer formation dynamics of a gas phase benzene dimer by picosecond pump–probe spectroscopy

2015 ◽  
Vol 17 (39) ◽  
pp. 25989-25997 ◽  
Author(s):  
Mitsuhiko Miyazaki ◽  
Masaaki Fujii
Keyword(s):  
Gas Phase ◽  
Vibrational Energy ◽  
Energy Redistribution ◽  
Pump Probe ◽  
Formation Dynamics ◽  
Benzene Dimer ◽  
Excimer Formation ◽  
Time Observation ◽  
Probe Spectroscopy ◽  
Real Time Observation

Photoexcitation of a T-shaped benzene dimer provides a sandwiched excimer in 10 ps accompanying a 1000 times faster intracluster vibrational energy redistribution rate than that of the benzene monomer.

scholarly journals Slow Relaxation Processes in SF6 Gas After Pumping by a CO2 Laser Pulse

1991 ◽  
Vol 11 (1) ◽  
pp. 39-48
Author(s):  
Iwao Kitazima ◽  
Hiroshi Iwasawa
Keyword(s):  
Molecular Diffusion ◽  
Vibrational Energy ◽  
Pump Intensity ◽  
Energy Relaxation ◽  
Probe Method ◽  
Relaxation Processes ◽  
Gas Cell ◽  
Vibrational Energy Relaxation ◽  
Pump Probe ◽  
Gas Cooling

The vibrational energy relaxation and distribution in SF6 at the collisional condition of 2 Torr was measured with the pump-probe method by use of two tunable CO2 300 ns-pulse lasers at the delay time up to 400 μs. The 10.6 μs P(30) pump intensity was 0.4 J/cm2. The probed spectra, divided into two parts, the induced transmission at the P(10)–P(22) and the absorption at the P(24)–P(32), were red-shifted by 50 μs and then slowly back to the initial. The time variation of induced signals was divided into the four regions due to the following processes; (I) the formation of nonthermal distribution in the ν3 mode and quasi-continuum with 1 μs, (II) the broad redistribution by the rise-up of vibrational temperature in 50 μs-duration, (III) the molecular diffusion or expansion out of the pumped region locally heated up by the V–T relaxation in another 60 μs, (IV) the gas cooling corresponding to the energy relaxation or population depletion over 400 μs. So, this pump-probe method at the collisional conditions will easily give us some informations, with a short gas cell and a suitable time scale, on those slow processes.

scholarly journals Vibrational Energy Relaxation in the (d, d) Excited State Of Nickel Octaethylporphyrin

1999 ◽  
Vol 19 (1-4) ◽  
pp. 275-277 ◽  
Author(s):  
Yasuhisa Mizutani ◽  
Yuki Uesugi ◽  
Teizo Kitagawa
Keyword(s):  
Excited State ◽  
Vibrational Energy ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Energy Relaxation ◽  
Electronic Relaxation ◽  
Vibrational Energy Relaxation ◽  
Time Resolved ◽  
Time Regime ◽  
Anti Stokes

The formation of a hot photoproduct of nickel octaethylporphyrin (NiOEP) upon ππ* excitation and its subsequent vibrational energy relaxation were monitored by picosecond time-resolved resonance Raman spectroscopy. Resonance Raman bands due to the photoproduct instantaneously appeared upon the photoexcitation. Their intensities decayed with a time constant of 330±20ps, which indicates electronic relaxation form the (d, d) excited state (B1g) to the ground state (B1g). Anti-Stokes ν4 band of the hot (d, d) excited state of NiOEP appeared immediately after the excitation and decayed with time constants of 11±2 and 330±40 ps. In contrast, the rise of anti- Stokes ν7 intensity was not instantaneous but delayed by 2.6±0.5 ps, which suggests that IVR has not been completed in a subpicosecond time regime.

Two-Dimensional Infrared Spectroscopy From the Gas to Liquid Phase: Density Dependent J-Scrambling, Vibrational Relaxation, and the Onset of Liquid Character

2019 ◽  
Author(s):  
Greg Ng Pack ◽  
Matthew Rotondaro ◽  
Parth Shah ◽  
Aritra Mandal ◽  
Shyamsunder Erramilli ◽  
...  
Keyword(s):  
Vibrational Energy ◽  
Rotational Relaxation ◽  
Vibrational Energy Relaxation ◽  
Pump Probe ◽  
Solution Dynamics ◽  
Supercritical Phase ◽  
Supercritical Solution ◽  
Asymmetric Stretch ◽  
Two Dimensional Infrared Spectroscopy ◽  
Vibrational Equilibrium

Ultrafast 2DIR spectra and pump-probe responses of the N2O n 3 asymmetric stretch in SF6 as a function of density from the gas to supercritical phase and liquid are reported. 2DIR spectra unequivocally reveal free rotor character at all densities studied in the gas and supercritical region. Analysis of the 2DIR spectra determines that J-scrambling or rotational relaxation in N2O is highly efficient, occurring in ~1.5 to ~2 collisions with SF6 at all non-liquid densities. In contrast, N2O n 3 vibrational energy relaxation requires ~15 collisions, and complete vibrational equilibrium occurs on the ~ns scale at all densities. An independent binary collision model is sufficient to describe these supercritical state point dynamics. The N2O n 3 in liquid SF6 2DIR spectrum shows no evidence of free rotor character or spectral diffusion. Using these 2DIR results, hindered rotor or liquid-like character is found in gas and all supercritical solutions for SF6 densities ³ r * = 0.3, and increases with SF6 density. 2DIR spectral analysis offers direct time domain evidence of critical slowing for SF6 solutions closest to the critical point density. Applications of 2DIR to other high density and supercritical solution dynamics and descriptions are discussed. <br>

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