Microwave spectrum, structure, and dipole moment of sulfuric acid

Monte Carlo Simulations of Small Sulfuric Acid−Water Clusters

“…59 Studies imply there must be rather complicated reaction schemes in order to account for the hydrogen transfer mechanisms between molecules/ions in these small clusters. 60 61 (where all sulfur-oxygen bonds are tetrahedrally coordinated around the sulfur) is used as a starting point for the SO 4 -2 geometry (see Figure 1 for details of the SO 4 2δ-structure). The sulfur atom in the sulfuric acid molecule is said to be "hypervalent", thus, allowing the sulfur atom to maintain two S-O single bonds and two SdO double bonds.…”

Effect of Molecular Structure and Hydration on the Uptake of Gas-Phase Sulfuric Acid by Charged Clusters/Ultrafine Particles

“…The comparison of the uptake coefficients calculated using Equation (2) with and without enhancement factors (EF) as a function of the particle diameter for (a) free sulfuric acid molecules, (b) monohydrates, (c) dihydrates, and (d) trihydrates at the ambient gas temperature of 300 K using the same input data set as that for Figure 1. and to study the hydration effect, we compared the uptake coefficients calculated using Equations (1) and (2). Figure 1 presents the upper and lower limits of the ratio between the uptake coefficients calculated using the maximum and minimum values of the dipole moments from Table 1 (EF upper , EF lower ) and those (EF ref ) calculated using the reference measured value of the dipole moment of sulfuric acid (2.73 D; Kuczkowski et al 1981) for (a) free sulfuric acid molecules, (b) monohydrates, (c) dihydrates, and (d) trihydrates. In order to estimate the overall effect, we included in Figure 1 the calculations performed using average value of the dipole moment for each group assuming the probability of the formation of different configurations to be equal (EF average ).…”

“…Nadykto and Yu (2003) showed that the enhancement in the attachment coefficient of the neutral molecule of free sulfuric acid to small ions/charged clusters may be as big as ∼10 in the lower troposphere, ∼15 in the polar stratosphere, and ∼20 in the mesosphere due to the high dipole moment of sulfuric acid molecule. Earlier measurement of sulfuric acid dipole moment (Kuczkowski et al 1981; this work contains the only measurement to our knowledge reported in the literature) indicated that sulfuric acid molecule has a dipole moment of 2.73 D. Recent theoretical calculations by Al Natsheh et al (2003) suggested that the gas-phase sulfuric acid molecules may have different equilibrium structures that give different dipole moments. Al Natsheh et al (2003) also found that gas phase sulfuric acid hydrates have wide variations in the equilibrium structures and dipole moments.…”

“…Such a big difference in the electrical properties (up to ∼1.34, 1.58, 2.60, and 2.14 times in the dipole moments of gas-phase sulfuric acid, mono-, di-, and trihydrate, respectively) is not surprising. Based on their own measurements of the structure and electrical dipole moment, Kuczkowski et al (1981) have predicted the existence of different modifications of gas-phase sulfuric acid that lead to the variations in the hydrates' structures and properties. Despite the wide variations of the dipole moments, the total bonding energies of the structures are pretty close within each group that is believed to indicate quite close probabilities of the formation for different structures.…”

“…The upper and lower limits of the ratio between the uptake coefficients calculated using the maximum and minimum values of the dipole moments from Kuczkowski et al 1981) for (a) free sulfuric acid molecules, (b) monohydrates, (c) dihydrates, and (d) trihydrates.…”