Multiphoton ionization and fragmentation of the hydrogen iodide molecule have been examined at 355 and 532 nm and optical field intensities of 1011−5×1012 W cm−2 by photoelectron spectroscopy and time-of-flight mass spectrometry. At 532 nm, scission of the H–I bond is favored over direct photoionization of the molecule. Three and four photon ionization of HI at 355 nm (ℏω≊3.5 eV), however, reveals clear vibrational progressions associated with the HI+ 2Π3/2 and 2Π1/2 ion product states. Analysis of these spectra yields vibrational frequencies for the 2Π3/2 and 2Π1/2 states that agree to better than 8% with those determined by Böwering et al. [Chem. Phys. Lett. 189, 467 (1992)] from single photon ionization experiments. Above threshold ionization (ATI) of both HI and atomic iodine are also observed.
Articles you may be interested inPhotoionization of iodine atoms: Rydberg series which converge to the I + ( S 1 0 ) ← I ( P 2 3 / 2 ) threshold Two well-developed Rydberg series of atomic iodine, built on the ...5s 2 5 p 4 3 P 1 ion core and assigned to nd͓2͔ 5/2 and ns͓1͔ 3/2 states with principal quantum numbers as high as nϭ47, have been observed by two photon ͑566рՇ600 nm͒ ionization of I(6s 2 P 3/2 ), and time-of-flight photoelectron spectroscopy and mass spectrometry. The data reported here extend the nd͓2͔ 5/2 and ns͓1͔ 3/2 series by 27 and 23 terms, respectively. The limit for both series, 91 387.9Ϯ1.3 cm Ϫ1 , revises upwards by 5.8 cm Ϫ1 the value for the I ϩ ( 3 P 1 ) state energy suggested by Minnhagen in 1962 ͓Ark. Fys. 21, 415 ͑1962͔͒. The quantum defects for the nd͓2͔ 5/2 and ns͓1͔ 3/2 series were determined to be 2.44Ϯ0.03 and 4.03Ϯ0.02, respectively. Several terms of a third, weaker series were also detected and tentatively assigned to nd͓2͔ 3/2 states, also having the 3 P 1 ion core. Photoelectron peaks associated with direct, five photon ionization of I 2 have been observed and are attributed to electronic autoionization of A 2 ⌸ (3/2)u ion core Rydberg states into the X 2 ⌸ (1/2)g,(3/2)g ionization continua.
RydbergRydberg state transitions of Ne& have been observed for the first time by laserexcitation spectroscopy. Molecular Rydberg states that have principal quantum numbers as large as 17 have been detected despite the predissociative nature of the high-lying Ne2 excited states.Several bands have been rotationally resolved and the rotational constant measured for the metastable 3so Z"+ state of the excimer agrees with theoretical (ab initio) predictions to within 4%.
The hydrogen fluoride laser has been used to successfully weld corneal tissue in vivo. Previous experiments have demonstrated the success of producing watertight welds in both porcine and human cadaver corneas.Wound bursting strengths of up to three times normal intraocular pressure have been reported.In this study, an in vivo model was utilized, specifically the rabbit cornea .Twelve New Zealand white rabbits received a 7 mm. , full thickness, linear corneal incision in one eye, and stay sutures were placed. Six of the wounds were welded with a semiconductor infrared laser, and six eyes served as controls. At two and four weeks, both histologic and tensiometric studies were performed. There was a trend toward increasing wound strength when the two and four week specimens were compared. Corneal welding may prove to be an adjunct to current suturing techniques in humans. Procedures requiring the closure of corneal incisions such as cataract extraction or penetrating keratoplasty may benefit from this technique.
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