K. P. Subramanian

Total electron scattering cross sections for argon, krypton and xenon at low electron energies

Absolute electron scattering cross sections for argon, krypton and xenon have been measured at low electron energies using the powerful technique of photoelectron spectroscopy. The measurements have been carried out at electron energies varying from 0.7 to 10 eV with an accuracy of +or-2.7%. The cross sections obtained have been compared with other recent measurements and theoretical computations.

Self-quenching and zero-pressure lifetime studies of NO2 at 465–490, 423–462 and 399–416 nm

Abstract The self-quenching and zero-pressure lifetimes for NO2 have been obtained from the lifetimes measured previously at different gas pressures by the pulse excitation technique in the three spectral regions 465–490, 423–462 and 399–416 nm at an interval of 0.2, 0.5 and 0.2 nm, respectively. The estimation of zero-pressure lifetimes and self-quenching rate constants has been carried out with an accuracy of ±5% and ±7%, respectively, for the static component of lifetime alone. The results obtained have been compared with other measurements where ever possible.

Lifetime measurements of NO2 in the predissociation region 399–416 nm

Abstract The fluorescence excitation spectra of NO2 have been studied and lifetimes have been measured in the first predissociation region at the excitation photon wavelengths 399–416 nm at an interval of 0.2 nm and at gas pressures 1, 3, 5, 7, 10 and 15 mTorr using an excimer laser pumped tunable dye laser as a photon source. Three groups of lifetimes have been obtained viz. 35–42, 80– 120 μs and of the order of 0.1 μs . The results obtained in the present experiment have been compared with other measurements where ever possible.

Total electron scattering cross sections for molecular oxygen at low electron energies

Absolute total electron scattering cross sections for molecular hydrogen have been measured at low electron energies using a photoelectron source. The measurements have been carried out at 25 electron energies varying from 0.2 to 10 eV with an accuracy of +or-2.7%. The cross sections obtained in the present experiment have been compared with others from recent measurements and theoretical computations.

Radiative Lifetime Measurements and Study of Perturbed Electronic States of NO2

Mixing of ro-vibrational levels in the excited states of certain molecules leads to elongation of average lifetime of excited states. The relaxation of pure adiabaticity condition of Born-Oppenheimer states allows mixing of levels in the excited state. The extent of perturbation on the emitting level by the nearby lying electronic states is ro-vibrational and is quantum number specific. This introduces variability in the anomalous lifetime as a function of the excitation wavelength. For certain wavelengths, emissions from pure unperturbed states also are observed. The radiative lifetime measurement of NO2 in the excitation region 465–490 nm is presented in this paper.

Total electron scattering cross-sections for carbon monoxide at low electron energies

Absolute total electron scattering cross-sections for carbon monoxide have been measured at low electron energies using a photoelectron source. The measurements have been carried out at 22 electron energies varying from 0.73 to 9.14 eV with an accuracy of ±3%. The cross-sections obtained in the present experiment have been compared with other measurements and theoretical computations.

Total electron scattering cross-sections for nitrous oxide at low electron energies

Absolute total electron scattering cross sections for nitrous oxide have been measured at low electron energies using a photoelectron source. The measurements have been carried out at 19 electron energies varying from 0.73–9.14 eV with an accuracy of ±3%. The cross sections obtained in the present experiment have been compared with other measurements.