Spectroscopy of molecules confined in solid para-hydrogen

Successive Hydrogenation of SO and SO2 in Solid para-H2: Formation of Elusive Small Oxoacids of Sulfur

“… Accordingly, the sample was irradiated at 365 nm for 60 min ( P ≈ 9 mW) originating from an optical parametric oscillator (OPO, GWU/Spectra-Physics VersaScan MB 240, full-width half-maximum, FWHM ≈ 5 cm –1 ) equipped with a frequency-doubling unit (Spectra-Physics uvScan) pumped by a pulsed Nd:YAG laser (Spectra-Physics Quanta Ray Lab 150, P ≈ 2.1–2.2 W, λ = 355 nm, f = 10 Hz, pulse duration = 2–3 ns). The formation of Cl atoms was monitored by measuring the intensity of the spin–orbit (SO) + Q 1 (0) transition at 5095 cm –1 caused by the simultaneous excitation of the Cl atom and a vibrational ( v ′ = 1, J ′ = 0 ← v ″ = 0, J ″ = 0) transition of a neighboring para -H 2 molecule . Cl atoms practically do not react with para -H 2 ; however, this reaction can be initiated by vibrationally exciting the para -H 2 molecules.…”

“…As described in detail in Section , H atoms were generated by the photolysis of the Cl 2 dopant at 365 nm and a subsequent 2217 nm NIR laser irradiation to initialize the reaction between Cl atoms and para -H 2 according to eqs and . The H atoms may react with the SO 2 molecules in the matrix, leading to the formation of numerous hydrogenated species, the isomers of HSO 2 and H 2 SO 2 .…”

“…Better quality MIR spectra were recorded after deposition averaging 128 scans. The purity of the para -H 2 was checked by collecting the NIR spectrum of the deposited matrix and measuring the relative absorption of the band belonging to o -H 2 (Q 1 (0) + S 0 (1) transition) at 4740 cm –1 . For this, the same spectrometer was used.…”

“…To keep the Cl 2 / para -H 2 ratio around 1:1000, the pressure in the Cl 2 tank and that of the gas mixture was continuously monitored throughout the deposition. For the H atom generation, the Cl 2 is photolyzed to produce Cl atoms. − Due to the diminished cage effect in para -H 2 , the two Cl atoms are separated and they do not recombine Accordingly, the sample was irradiated at 365 nm for 60 min ( P ≈ 9 mW) originating from an optical parametric oscillator (OPO, GWU/Spectra-Physics VersaScan MB 240, full-width half-maximum, FWHM ≈ 5 cm –1 ) equipped with a frequency-doubling unit (Spectra-Physics uvScan) pumped by a pulsed Nd:YAG laser (Spectra-Physics Quanta Ray Lab 150, P ≈ 2.1–2.2 W, λ = 355 nm, f = 10 Hz, pulse duration = 2–3 ns).…”

“…A gold-plated silver wafer mounted to the cold finger of an RDK-415D2 cryostat (Sumitomo Heavy Industries Inc.) that allowed for cooling it down to 3.1 K served as a substrate whereupon the deposition of the matrix occurs. 130 For this, the same spectrometer was used. Two hundred and fifty-six scans were averaged for the NIR spectra between 9000 and 600 cm −1 with a resolution of 0.5 cm −1 using the same MCT detector.…”