Hydration of ammonia and hydrogen chloride at cryogenic temperature studied by TP-TOF-SIMS

Probing Difference in Diffusivity of Chloromethanes through Water Ice in the Temperature Range of 110−150 K

“…Another technique, namely, secondary ion mass spectrometry (SIMS), has emerged as one of the most surface-sensitive techniques and is being used for studying molecular solids. Temperature-programmed time-of-flight SIMS (TP-TOF-SIMS) has been used to study differences in the hydration of polar and nonpolar molecules as a function of temperature. , An alternative to SIMS is low-energy surface scattering or so-called chemical sputtering (CS) . This is also called as low-energy sputtering (LES), which has also been used for surface studies .…”

Uptake of NH3 and NH3 + HOBr Reaction on Ice Surfaces at 190 K

“…15 The uptake coefficient for NH 3 at the water interface is (9.7 ( 0.9) × 10 -2 at T ) 290 K. 17 Davidovits and co-workers show that the uptake coefficient of NH 3 on water has strong negative temperature dependence, increasing from 0.1 at 290 K to 0.3 at 260 K. 16,25 The interactions between NH 3 and H 2 O molecules are weaker than those between HCl and H 2 O molecules. 26 NH 3 efficiently scavenges HOBr to form NH 2 Br in the aqueous phase. 27 Halogenation of NH 3 has relevant roles in biochemistry and environmental chemistry.…”

Vacuum ultraviolet photodissociation and surface morphology change of water ice films dosed with hydrogen chloride

“…And then, the substrate temperature was reduced to 100 K during the TOF measurements. In the obtained TOF spectra, the contributions of components B and C gradually decreased with T s up to 140 K, and finally disappeared at 145 K. The surface composition of the thusprepared film is not changed by cooling it from 140 to 100 K. 10 C. Time-of-flight spectra of chlorine atoms from the photodissociation of molecular HCl adsorbed on water ice films at 157 nm Figure 5 shows the TOF spectra of Cl͑ 2 P 3/2 ͒ and Cl * ͑ 2 P 1/2 ͒ atoms from the 157 nm photodissociation of ASW films dosed with HCl ͑1 ML͒ at 100 K. The TOF spectra are reproduced by a combination of the Gaussian and MB distributions. The Gaussian distribution of Cl͑ 2 P 3/2 ͒ is characterized by ͗E t ͘ Cl = 1.4± 0.1 eV, w Cl = 0.9± 0.1 eV contributing ͑2±1͒%.…”

“…20 As shown in Fig. 7, there are numerous reports of studies on the interactions of HCl with ice films with various experimental methods: temperature-programed desorption mass spectrometry ͑TPDMS͒, 15 infrared spectroscopy, 17,21,22 secondary ion mass spectroscopy, 10,23,24 laser thermal desorption, 25 reactive ion scattering ͑RIS͒, 3,7,14 near-edge x-ray absorption fine structures ͑NEXAFSs͒, 26 electron-stimulated desorption, 27 and molecular beam scattering techniques. 28,29 The RIS study suggests that for temperatures below 80 K molecular adsorption dominates, while the amount of ionic species increases until an ice temperature of 140 K is reached.…”