Temperature-dependent optical constants of liquid isopropanol, n-butanol, and n-decane

Abstract

Liquid isopropanol, n-butanol, and n-decane are combustible organic compounds that are frequently used in theoretical and experimental researches on fuel combustion. In this work, the temperature-dependent optical constants of liquid isopropanol, n-butanol, and n-decane in the region 500-5500 cm at ambient pressure are measured using the combined ellipsometry-transmission method. In the combined method, the optical constants are first measured by a modified ellipsometry method, and then the absorption indices for weak absorption regions are obtained by the transmission method using the refractive indices measured by the modified ellipsometry method. The refractive indices of liquid isopropanol, n-butanol, and n-decane are within the range from 1.3 to 1.45 in the studied wavelength and temperature region. The absorption indices of these liquids range from 10 to 10. In the temperature range studied, the refractive indices decrease with increasing temperature in an approximately linear manner, but the effects of the temperature on the absorption indices are much smaller. The characteristic wavenumbers of the main absorption peaks are consistent with the vibrational frequencies of major functional groups.

Modeling Thermal Radiation in Combustion Environments: Progress and Challenges

“…Many of these studies are focused on single-component fuels. For example, data are available from several researchers on the spectral variation of the complex index of refraction of iso-pentane [96], iso-octane [96], n-hexane [96], n-heptane [96][97][98], n-nonane [96], n-decane [96][97][98][99], n-hexene [96], o-xylene [96], and toluene [96], isopropanol [99], and n-butanol [99]. Although many of these components are the components of real fuels, the radiative properties of real fuels such as Diesel vary noticeably from these components.…”

Development of full spectrum correlated k-model for spectral radiation penetration within liquid fuels

“…314487 and the Finish Fire Protection Fund (PSR). The kind help of Professor Lin-hua Liu in providing the tabulate data of decane complex index of refraction published in [32] is greatly acknowledged.…”

Combining ab initio and ab initio molecular dynamics simulations to predict the complex refractive indices of organic polymers

“…14,15 We have applied the state-of-the-art ab initio molecular dynamics (AIMD) method to calculate the dielectric functions of liquid isopropanol, n-butanol, and n-decane in the spectral range of 500–5500 cm −1 . 16 In the previous study, the imaginary part of the complex dielectric function was obtained by Fourier transforming the autocorrelation function of the system total dipole moment, and then the real part of the complex dielectric functions was calculated using the Kramers–Kronig (K–K) dispersion relation with a known high-frequency dielectric function. 17 Thus, the choice of the high-frequency dielectric function affects the correctness of the simulation results directly.…”