The infrared optical constants of sulfuric acid at 250 K*

Enhanced low-temperature lithium storage performance of multilayer graphene made through an improved ionic liquid-assisted synthesis

“…S1, the IR spectrum of MW 100 exhibits extremely low absorption baseline characteristic of high carbon content materials [27]. The drastic decrease of the absorption bands in the region 500e700 cm À1 , which are characteristic of the intercalated species in expandable graphite (e.g., H 2 SO 4 , SO 3 and SO 2 ) [25,28,29], is a further evidence of their release upon the expansion process. Moreover, the elemental analysis (EA) performed at each step of the process (see Table 1) confirms the elimination of the intercalated species and the achievement of high carbon content (i.e.…”

A Temperature- and Composition-Dependent Study of H2SO4 Aerosol Optical Constants Using Fourier Transform and Tunable Diode Laser Infrared Spectroscopy

“…Previous studies of the frequency-dependent optical constants of sulfuric acid have been carried out on bulk solutions over a limited range of temperatures and compositions. − Of these, the data sets of Palmer and Williams (PW) 6 are the most widely used in atmospheric studies, − even though the measurements were all performed at room temperature. The PW results do show that the refractive indices of sulfuric acid depend strongly upon the composition, normally quoted in sulfuric acid weight percent (wt %).…”

Infrared absorption by volcanic stratospheric aerosols observed by ISAMS

“…Within this band neither the real nor the imaginary part of the refractive index changes monotonically with H2SO4 concentration. The imaginary component of the refractive index reaches a minimum at about 8.5 gm, which corresponds to the region of maximum absorption by the H2SO4 drops.One further consideration is the applicability of the Palmer and Williams' data to stratospheric aerosols whose temperatures are typically in the range 210-250 K. Far from absorption bands the refractive index can be extrapolated to lower temperatures using the Lorentz-Lorenz correction as verified byPinkley and Williams [1976] who presented measurements at temperatures 250 K and 300 K Halperin and Murcray [1987]. estimated the difference in the refractive index at 215 K, compared to 300 K, for the spectral region between 8 gm and 13 gm.…”