Augustinus Asenbaum | University of Salzburg (original) (raw)

Uploads

Papers by Augustinus Asenbaum

Advances in Molecular Relaxation Processes, 1978

ABSTRACT

Journal of Molecular Liquids, Jun 1, 1983

... Applying this theory to the case of dipole rotation Eyring defined k' as the number of t... more ... Applying this theory to the case of dipole rotation Eyring defined k' as the number of times per second the dipole acquires sufficient energy to ... Temp ao a' a'' a-K Dimethyl sulphoxide 298 23.00 5.50 7.80 0.38 + 306 20.00 5.53 7.00 0.33 Phenol 314 19.23 5.92 6.50 0.24 322 ...

Springer proceedings in physics, 1985

Brillouin spectra of liquid carbon tetrachloride and benzene have been measured at high pressures... more Brillouin spectra of liquid carbon tetrachloride and benzene have been measured at high pressures up to 1500 bars and at temperatures between 298 and 348 K. From the experimental spectra the energy vibrational relaxation time τ was determined as a function of pressure. At constant temperature τ decreases with increasing density and at constant density τ decreases with increasing temperature.

Molecular Physics, Jun 20, 2000

We report results on the concentration dependence of the non-coincidence effect in the upsilon(C ... more We report results on the concentration dependence of the non-coincidence effect in the upsilon(C O) mode in N,N-dimethylformamide-CCl4 mixtures. This study has been mainly addressed to the investigation of the experimentally observed sign inversion for this quantity in the low concentration range of chemical mixtures, which is also reported in the literature. We argue that the sign inversion of the

Journal of Chemical Physics, Jun 1, 1979

The temperature dependence of the vibrational relaxation time τvib of pure liquid CHCl3 was deter... more The temperature dependence of the vibrational relaxation time τvib of pure liquid CHCl3 was determined by Brillouin scattering between −5 and +55 °C. From the experimental results the number of intermolecular collisions Z10 necessary for the deactivation of the lowest vibrational mode has been calculated using the moving wall cell model. In contrast to other liquids no linear relationship between lnZ10 and (1/T)1/3 could be found. Different reasons for this behavior, which possibly is due to the weak dipole moment of CHCl3, are discussed.

Advances in Molecular Relaxation and Interaction Processes, Oct 1, 1978

Abstract The vibrational relaxation time of liquid CCl4 was measured as a function of temperature... more Abstract The vibrational relaxation time of liquid CCl4 was measured as a function of temperature in a Brillouin-scattering experiment. Between −5°C and 65°C the relaxation time τvib decreases from 160 psec to 145 psec. The nonrelaxing fraction of the bulk viscosity was found to be 1.5 to 2.5 times the shear viscosity.

Journal of Chemical Physics, Dec 15, 1993

The vibrational band shapes and their parameters of the C–H vibration of CH2I2 diluted with liqui... more The vibrational band shapes and their parameters of the C–H vibration of CH2I2 diluted with liquid CCl4 were measured as a function of composition. The linewidth increases from 8.7 cm−1 with decreasing mole fraction X of CH2I2 reaches a maximum value of 15.92 cm−1 near X=0.4 and decreases again in the limit of the diluted case. The frequency of the band center increases with decreasing X from 2965.37 to 2984.75 cm−1. These results are compared with the model of Knapp and Fischer for the concentration dependence of the vibrational linewidths and shifts. For the line shift, good agreement is found between theory and experiment by introducing a microscopic mole fraction. The model can be used to get an estimation on the difference between macroscopic and microscopic concentration. The predictions for the band shape are rather satisfactory in the whole concentration range. Deviations are due to the assumption that the band shapes in the model are Lorentzian for both neat liquids, whereas the experimental line shape in neat CH2I2 is not.

Advances in Molecular Relaxation and Interaction Processes, Mar 1, 1982

From Brillouin spectra of tetrachloromethane, benzene and cyclohexane measured between 283.15 K a... more From Brillouin spectra of tetrachloromethane, benzene and cyclohexane measured between 283.15 K and 343.15 K, and carefully re-evaluated data for the heat capacities at constant pressure CP, and constant volume C,,, the vibrational contribution to CV was determined and compared with calculated values obtained from the Planck-Einstein relation. Utilizing perfect gas state heat capacity data, the residual heat capacity Ci was determined and subsequently used to present an estimate for the residual rotational heat capacity (external rotation).

Chemischer Informationsdienst, May 5, 1981

Measurement Science and Technology, Nov 20, 2000

The absolute refractive index of liquid sulphur dioxide (SO 2) was determined with an uncertainty... more The absolute refractive index of liquid sulphur dioxide (SO 2) was determined with an uncertainty of ±0.0007 with the help of a Michelson interferometer and a computer-controlled rotatory stage supporting a rectangular fused silica cell, containing the liquid. The measurements were performed at temperatures around 20 • C for the laser line wavelengths 632.8, 514.5 and 488.0 nm. The experimental data were fitted to the simple Cauchy dispersion formula. The results calculated from this formula are consistent within the experimental uncertainty with published values obtained at other wavelengths and/or other temperatures.

European Journal of Mineralogy, 2001

Processes, 1982

The temperature dependence of the ultrasonic velocity and ultransonic damping as well as the hype... more The temperature dependence of the ultrasonic velocity and ultransonic damping as well as the hypersonic velocity and relaxation time 51 was measured in liquid cyclohexane by Brillouin scattering. These data suggest a two-step relaxation process for the vibrational relaxing specific heat.

Molecular Physics, Sep 1, 1997

Journal of Applied Physics, Feb 14, 2013

Advances in Molecular Relaxation Processes, 1978

ABSTRACT

Journal of Molecular Liquids, Jun 1, 1983

... Applying this theory to the case of dipole rotation Eyring defined k' as the number of t... more ... Applying this theory to the case of dipole rotation Eyring defined k' as the number of times per second the dipole acquires sufficient energy to ... Temp ao a' a'' a-K Dimethyl sulphoxide 298 23.00 5.50 7.80 0.38 + 306 20.00 5.53 7.00 0.33 Phenol 314 19.23 5.92 6.50 0.24 322 ...

Springer proceedings in physics, 1985

Brillouin spectra of liquid carbon tetrachloride and benzene have been measured at high pressures... more Brillouin spectra of liquid carbon tetrachloride and benzene have been measured at high pressures up to 1500 bars and at temperatures between 298 and 348 K. From the experimental spectra the energy vibrational relaxation time τ was determined as a function of pressure. At constant temperature τ decreases with increasing density and at constant density τ decreases with increasing temperature.

Molecular Physics, Jun 20, 2000

We report results on the concentration dependence of the non-coincidence effect in the upsilon(C ... more We report results on the concentration dependence of the non-coincidence effect in the upsilon(C O) mode in N,N-dimethylformamide-CCl4 mixtures. This study has been mainly addressed to the investigation of the experimentally observed sign inversion for this quantity in the low concentration range of chemical mixtures, which is also reported in the literature. We argue that the sign inversion of the

Journal of Chemical Physics, Jun 1, 1979

The temperature dependence of the vibrational relaxation time τvib of pure liquid CHCl3 was deter... more The temperature dependence of the vibrational relaxation time τvib of pure liquid CHCl3 was determined by Brillouin scattering between −5 and +55 °C. From the experimental results the number of intermolecular collisions Z10 necessary for the deactivation of the lowest vibrational mode has been calculated using the moving wall cell model. In contrast to other liquids no linear relationship between lnZ10 and (1/T)1/3 could be found. Different reasons for this behavior, which possibly is due to the weak dipole moment of CHCl3, are discussed.

Advances in Molecular Relaxation and Interaction Processes, Oct 1, 1978

Abstract The vibrational relaxation time of liquid CCl4 was measured as a function of temperature... more Abstract The vibrational relaxation time of liquid CCl4 was measured as a function of temperature in a Brillouin-scattering experiment. Between −5°C and 65°C the relaxation time τvib decreases from 160 psec to 145 psec. The nonrelaxing fraction of the bulk viscosity was found to be 1.5 to 2.5 times the shear viscosity.

Journal of Chemical Physics, Dec 15, 1993

The vibrational band shapes and their parameters of the C–H vibration of CH2I2 diluted with liqui... more The vibrational band shapes and their parameters of the C–H vibration of CH2I2 diluted with liquid CCl4 were measured as a function of composition. The linewidth increases from 8.7 cm−1 with decreasing mole fraction X of CH2I2 reaches a maximum value of 15.92 cm−1 near X=0.4 and decreases again in the limit of the diluted case. The frequency of the band center increases with decreasing X from 2965.37 to 2984.75 cm−1. These results are compared with the model of Knapp and Fischer for the concentration dependence of the vibrational linewidths and shifts. For the line shift, good agreement is found between theory and experiment by introducing a microscopic mole fraction. The model can be used to get an estimation on the difference between macroscopic and microscopic concentration. The predictions for the band shape are rather satisfactory in the whole concentration range. Deviations are due to the assumption that the band shapes in the model are Lorentzian for both neat liquids, whereas the experimental line shape in neat CH2I2 is not.

Advances in Molecular Relaxation and Interaction Processes, Mar 1, 1982

From Brillouin spectra of tetrachloromethane, benzene and cyclohexane measured between 283.15 K a... more From Brillouin spectra of tetrachloromethane, benzene and cyclohexane measured between 283.15 K and 343.15 K, and carefully re-evaluated data for the heat capacities at constant pressure CP, and constant volume C,,, the vibrational contribution to CV was determined and compared with calculated values obtained from the Planck-Einstein relation. Utilizing perfect gas state heat capacity data, the residual heat capacity Ci was determined and subsequently used to present an estimate for the residual rotational heat capacity (external rotation).

Chemischer Informationsdienst, May 5, 1981

Measurement Science and Technology, Nov 20, 2000

The absolute refractive index of liquid sulphur dioxide (SO 2) was determined with an uncertainty... more The absolute refractive index of liquid sulphur dioxide (SO 2) was determined with an uncertainty of ±0.0007 with the help of a Michelson interferometer and a computer-controlled rotatory stage supporting a rectangular fused silica cell, containing the liquid. The measurements were performed at temperatures around 20 • C for the laser line wavelengths 632.8, 514.5 and 488.0 nm. The experimental data were fitted to the simple Cauchy dispersion formula. The results calculated from this formula are consistent within the experimental uncertainty with published values obtained at other wavelengths and/or other temperatures.

European Journal of Mineralogy, 2001

Processes, 1982

The temperature dependence of the ultrasonic velocity and ultransonic damping as well as the hype... more The temperature dependence of the ultrasonic velocity and ultransonic damping as well as the hypersonic velocity and relaxation time 51 was measured in liquid cyclohexane by Brillouin scattering. These data suggest a two-step relaxation process for the vibrational relaxing specific heat.

Molecular Physics, Sep 1, 1997

Journal of Applied Physics, Feb 14, 2013