Ion Mobility-Mass Spectrometry of Iodine Pentoxide–Iodic Acid Hybrid Cluster Anions in Dry and Humidified Atmospheres

Abstract

Nanometer scale clusters form from vapor phase precursors and can subsequently grow into nanoparticles during atmospheric nucleation events. A particularly interesting set of clusters relevant to nucleation is hybrid iodine pentoxide-iodic acid clusters of the form (I 2 O 5) x (HIO 3) y , as these clusters have been observed in coastal region nucleation events in anomalously high concentrations. To better understand their properties, we have utilized ion mobility-mass spectrometry to probe the structures of cluster anions of the form (I 2 O 5) x (HIO 3) y (IO α)-(x = 0-7, y = 0-1, α = 1-3), similar to those observed in coastal nucleation events. We show that (I 2 O 5) x (HIO 3) y (IO α)clusters are relatively stable against dissociation during mass spectrometric measurement, as compared to other clusters observed in nucleation events over continental sites, and that at atmospherically relevant relative humidity levels (65% and less), clusters can become sufficiently hydrated to facilitate complete conversion of iodine pentoxide to iodic acid, but that water sorption beyond this level is limited, indicating that the clusters do not persist as nanometer scale droplets in the ambient.

Frequent new particle formation over the high Arctic pack ice by enhanced iodine emissions

“…Khanniche et al 85 showed that HIO 3 forms stable hydrates with up to two water molecules but did not investigate larger hydrates. It has also been suggested that the iodate dimer (HIO 3 IO 3 − ) is hydrated with up to 5 water molecules at 65% RH 86 . Therefore, we assumed the HIO 3 monomer to be prevalently bound to three water molecules and estimated its volume based on bulk-phase density measurements 87 .…”

Global optimization of chemical cluster structures: Methods, applications, and challenges

“…The development of GO as implemented in ABCluster, has eliminated this obstacle to a large extent, making a series of productive NPF studies possible [32, 96, 167, 172–197] and revealing valuable insights into atmospheric chemistry (see Figure 7 for some examples). ABCluster has been regarded as a standard tool in this field [198–200].…”

“…Example GMs of molecular clusters obtained with ABCluster: [106, 119] (A) (HNO 3 ) 3 (NH 3 ) 3 (H 2 O) 2 [167], (B) (H 2 NSO 3 H)(H 2 SO 4 ) 2 ((CH 3 ) 2 NH) 3 [176], (C) [96], (D) (Gly) 2 (H 2 SO 4 )(NH 3 ) 2 [184]…”

NWPEsSe: An Adaptive-Learning Global Optimization Algorithm for Nanosized Cluster Systems

“…[48][49][50][51][52][53][54][55][56][57] Another example is that several authors searched the GMs of clusters consisting of atmosphere related molecules like water, ammonia, nitric acid, hydroxymethanesulfonic acid, sulfuric anhydride, and pentoxide−iodic acid. [58][59][60][61][62][63][64][65][66][67][68][69][70] Using GMs of different sizes, atmospheric cluster dynamics equations can be solved 71 and a lot of atmospheric chemical phenomena were successfully explained. [58][59][60][61][62][63][64][65][66][67][68][69][70] ABCluster was also applied in catalysis, 4,[72][73][74] material science, [75][76][77] solution chemistry, [78][79][80] etc.…”