zhu_2006#
J. Zhu, W. Guo, Y. Wang and L. Wang, “Dissociation of NO2 in femtosecond intense fields”, Chin. Sci. Bull. 51, 1185 (2006)
Source record · Catalogue · Review register
DOI: 10.1007/s11434-006-1185-2
Source kind: measurement
Recorded technique: Time-of-flight mass spectrometry of NO2 (2 % in Ar, pulsed valve, 0.5 mm orifice) in a home-made solid-state femtosecond laser at 810 nm (~50 nm bandwidth, about 60 fs by single-shot autocorrelation, 20 Hz) and its second (405 nm) and third (270 nm) harmonics from BBO, focused by a 30 cm fused-quartz lens; intensity varied by neutral-density attenuators; 40 cm field-free flight, two-stage microchannel plates, each spectrum averaged over 532 shots (p. 1186).
Materials in structured entries: NO2
Dataset quantities: fragmentation_branching_ratio
Contents: 2 datasets; 0 formulas.
Curation notes#
Journal pp. 1185-1190 = pdf pages 1-6. Identity checked on pdf page 1 (title, authors, Chin. Sci. Bull. 51(10) 1185-1190, DOI).
INTENSITIES (p. 1186): ‘estimated to vary from 1.12 x 10^15 to 2.48 x 10^15 W/cm2 for 800 nm, from 1.43 x 10^15 to 3.86 x 10^15 W/cm2 for the SHG light and from 0.11 x 10^14 to 1.62 x 10^14 W/cm2 for THG’. How they were estimated is not stated; the Keldysh parameters quoted (0.18-0.26 at 810 nm, 0.28-0.47 at 405 nm, 2.1-8.0 at 270 nm) follow from them. Doubt: no calibration or uncertainty is given, so the ranges are nominal; which intensity each typical spectrum of Fig. 1 had is not stated. The pulse durations at 405 and 270 nm are not stated (‘kept quite similarly’, p. 1186).
POLARISATION (doubt, TC-967): ‘The laser polarizations of 810, 405 and 270 nm are set to be perpendicular to the detector’ (p. 1186), but ‘the polarizations of employed laser are parallel to the time of flight axis’ (p. 1189). Linear in both statements.
TEXT VALUES (pp. 1186-1187; TC-967): at 810 nm ‘the parent ion is about three times stronger than fragment ion NO+ while no other fragment ion can be detected’; at 405 nm ‘NO+ becomes about threefold stronger than the parent ion, while tiny O+ is observed’; at 270 nm ‘NO+ becomes almost equal to that of NO2+, while further fragment ions, N+ and O+, increase remarkably’ (no number; not taken). These describe the ‘typical’ spectra of Fig. 1, intensity not stated for each. The NO2+/NO+ ratios are ‘independent of the laser intensity’ at each wavelength (abstract; Fig. 3).
SLOPES (notes only; log-log slopes of the yields against intensity, Fig. 2): 810 nm NO2+ 5.0, NO+ 4.8, N+ and O+ ‘about 11’ (‘twice of those of NO2+ and NO+’); 405 nm NO2+ 3.5, NO+ 3.2, O+ and N+ close to those; 270 nm NO2+ and NO+ 1 (pp. 1187-1188). No quantity holds a yield’s slope. The paper reads the equal slopes of NO2+ and NO+ as NO+ coming from the field-induced dissociation of NO2+ (not neutral dissociation followed by ionisation, as Singhal et al. proposed), and the absence of double peaks as ‘little kinetic energy released’ in forming N+, O+ and NO+ (p. 1189). The 405 nm photon reaches the NO2 A 2B2 state (conical intersection with X 2A1, below 397.9 nm).
QUOTED (not taken): ionisation potentials NO2 9.6 eV, NO 9.3 eV; appearance potentials of NO+ (12.3 eV) and O+ (16.8 eV) from neutral NO2 (pp. 1187-1188).
FIGURES FOR LATER (TC-967; raster, embedded images): Fig. 3, NO2+/NO+ against the Keldysh parameter at the three wavelengths (the ratios this paper is about); Fig. 2, the ion yields against intensity, log-log; Fig. 1, the mass spectra.
Recorded bibliographic identity status: VALIDATED. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
zhu_2006/parent_over_NOplus_810#
{
"id": "parent_over_NOplus_810",
"material": "NO2",
"table": "text",
"quantity": "fragmentation_branching_ratio",
"unit": "1",
"abscissa": "none",
"use": "check",
"parameters": {
"channel": "NO2+ (no dissociation)",
"reference": "NO+ + O",
"excitation": "strong-field pulse",
"wavelength_nm": 810,
"pulse_fs": 60,
"polarization": "linear (perpendicular or parallel to the TOF axis: the paper says both)",
"detection_correction": "none stated",
"intensity_range": "1.12e15-2.48e15 W/cm2, estimated (p. 1186); the spectrum's own intensity not stated"
}
}
1 inline points in the source record.
p. 1186 (TC-967): at 810 nm ‘the parent ion is about three times stronger than fragment ion NO+ while no other fragment ion can be detected’, from the typical spectrum of Fig. 1(a); the ratio is independent of intensity over the range (Fig. 3). Printed as ‘about three times’; no uncertainty. The channel is the undissociated parent over NO+, as printed (NO+/NO2+ about 1/3).
zhu_2006/NOplus_over_parent_405#
{
"id": "NOplus_over_parent_405",
"material": "NO2",
"table": "text",
"quantity": "fragmentation_branching_ratio",
"unit": "1",
"abscissa": "none",
"use": "check",
"parameters": {
"channel": "NO+ + O",
"reference": "NO2+ (the parent ion)",
"excitation": "strong-field pulse",
"wavelength_nm": 405,
"polarization": "linear (perpendicular or parallel to the TOF axis: the paper says both)",
"detection_correction": "none stated",
"intensity_range": "1.43e15-3.86e15 W/cm2, estimated (p. 1186); the spectrum's own intensity not stated"
}
}
1 inline points in the source record.
p. 1187 (TC-967): at 405 nm ‘NO+ becomes about threefold stronger than the parent ion, while tiny O+ is observed’ (Fig. 1(b)); NO+ ‘always dominate[s] the mass spectra’ at 405 nm (p. 1188). Printed as ‘about threefold’; no uncertainty. The pulse duration at 405 nm is not stated (similar to 810 nm’s 60 fs, p. 1186).
Formulas#
No formulas are recorded.
Corrections#
No dataset errata are recorded in this source record.
Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the review register for the checks and decisions.