First-stage enrichment in CO2-laser-induced13C separation by a two-stage IRMPD process: IRMPD of CHClF2/Br2 mixtures

13C-selective infrared multiple photon dissociation of β-propiolactone by a free electron laser

“…The observed selectivity of $130 for b-propiolactone in the present study using FEL-TUS is considerably larger than the selectivities obtained previously with CO 2 laser or FEL irradiation of various compounds [3][4][5][6][7][8][9]17,18]. The theoretical calculation of fundamental molecular vibrations estimates an isotope shift of $47 cm À1 (Table 2) between the @ 12 C@ 16 O peak at 1869 cm À1 and the @ 13 C@ 16 O peak at around 1822 cm À1 .…”

“…Arai and his coworkers have reported the two-stage enrichment of 13 C (natural 13 C/ 12 C = 1.1/98.9), where the first stage is the 13 C-selective IRMPD of CHClF 2 in the presence of Br 2 and the second stage is the 13 C selective IRMPD of the first-stage product, CBr 2 F 2 [5][6][7]. The atom fraction of 13 C in the main product of the second stage, C 2 Br 2 F 4 , has been found to be as high as about 85%.…”

“…A large isotope effect is one of the unique characteristics in IRMPD, which is applicable to practical isotope separation of several elements such as carbon [4][5][6][7][8][9], oxygen [10,11], and silicon [12][13][14][15].…”

High Enrichment of28Si by Infrared Multiple Photon Decomposition of Si2F6

“…1,2) Since early observations on isotope effects by Letokhov et al, many efforts have been made for the application of IRMPD to practical isotope separation. [3][4][5][6][7][8][9][10][11][12][13][14][15] Most studies are concerned with 13 C separation by IRMPD of fluorohydrocarbons. Baranov has reported the production of enriched 12 C (atomic fraction, 99.99%; production rate, 1 g/h) by IRMPD of natural CF 3 I using a high repetition CO 2 laser.…”

Multiphoton Isotope-Selective Dissociation of Formic Acid Molecules under Action of a Free Electron Laser

“…A very large body of experimental and theoretical work on infrared multiphoton dissociation (MPD) has been accomplished since such reactions were first described over 20 years ago. − Of that work, a substantial proportion is concerned with isotope-specific MPD. − Isotopic enrichment in the gas phase of small molecules has been accomplished for sulfur, − oxygen, − hydrogen, − silicon 24 and multiple elements from the same compound. − The most extensive work has been done on carbon isotopes and most often with CO 2 lasers. − Carbon istotopic enrichment has been observed in single-wavelength, single-component reactants, − multiple-wavelength (usually two or more CO 2 laser lines) conditions 28-30 and in two-component, two-step processes. − …”