Search results for "Spectroscopy."

Rotational collisional line broadening at high temperatures in the N2 fundamental Q-branch studied with stimulated Raman spectroscopy

1986

Self broadened N 2 Q-branch spectra are measured by high resolution stimulated Raman spectroscopy in the pressure region 0.25-1.9 atm. and in the temperature range 295-1310 K. Non additivity of the Q(J) components due to line overlap arising in the highest pressure range explored is carefully taken into account. Excellent fit of the whole spectra is thus obtained for each pressure with linearly density-dependent line widths. Semi-classical calculations of the line-broadening coefficients lead to consistent values with all the measured ones. These calculations are extended to higher J values and to higher temperatures (up to 2500 K). At last, a simple phenomenological model based on a polyno…

Spontaneous Raman Scattering Spectrum of Gaseous IrF6 in the Ground Electronic State

1996

Stimulated Raman spectroscopy as the essential tool for studying collisional effects : application to combustion

1994

No abstract available

Collisional Relaxation Processes Studied by Coherent Raman Spectroscopy for Major Species Present in Combustions

1992

The effects of collisional relaxation processes on the Q-branch profile of major species present in combustions have been studied by high resolution stimulated Raman spectroscopy. Particular interest has focused on the following collisional systems: N2-N2, O2-O2, CO2-CO2, O2-N2, N2-CO2 and N2-H2O. For each colliding pair, starting from accurate determinations of line broadening coefficients over a wide temperature range, state-to-state rates for rotational energy transfers have been deduced by using various fitting laws. Among these rate laws, special attention has been paid to the temperature dependence of the energy corrected scaling (ECS) law combined with a hybrid exponential-power law …

Impulsive excitation of high vibrational states in I2–Xe complex on the electronic ground state

2010

Abstract High vibrational states, up to ν  = 22, are excited and investigated on the ground electronic state of a 1:1 I 2 –Xe complex isolated in solid Kr using femtosecond CARS technique and spontaneous resonant Raman measurements. The results show that this system is a promising candidate for investigations of coherent control of bimolecular reactions by using vibrational wavepackets on the ground electronic state.

On the biradicaloid nature of long quinoidal oligothiophenes: experimental evidence guided by theoretical studies.

2007

ChemInform Abstract: Assignment of the Absolute Configuration and Total Synthesis of (+)-Caripyrin.

2015

The antifungal secondary metabolite (+)-caripyrin was studied by vibrational circular dichroism spectroscopy. Analysis of the recorded data, with the Boltzmann weighted-average of the spectra calculated at the B3LYP/6-311G(d,p) level of theory for all relevant conformers, unequivocally proved the (R,R)-configuration for the dextrorotatory natural product. Based on this finding, a short enantioselective synthesis of (+)-caripyrin was developed.

Enhanced Debye level in nano Zn1+xSb, FeSb2, and NiSb: Nuclear inelastic spectroscopy on121Sb (Phys. Status Solidi B 5/2014)

2014

Raman measurements in the intermediate phase of [N(CH3)4]2ZnI4

1991

Abstract Raman spectra and deviation angle of the indicatrix have been measured in the intermediate phase, between the two transition temperatures T c1 = 255 K and T c2 = 217 K. The results are consistent with the existence, in this phase, of large domains, piled up along the c-axis (Pnma notation).

Excitation Energy-Transfer in the LH2 Antenna of Photosynthetic Purple Bacteria via Excitonic B800 and B850 States

2000

A newly developed CIEM method that uses a combination of semi-empirical or ab-initio configuration interaction methods and exciton theory to predict electronic energies, eigenstates, absorption and CD spectra of aggregated chromophoric systems with environmental interactions included is extended and used for estimation of excitation energy transfer rates. Excitonic energy levels of the two ring systems the B800 and the B850 of the light harvesting antenna LH2 of Rhodopseudomonas acidophila and the corresponding absorption spectrum were calculated by assuming inter-ring interactions to be zero. Excitation energy transfer rates were calculated by using the Fermi Golden rule with the dipole - …