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1.
In the 9387–9450 cm–1 region at temperatures of 300–1000 K, we have used an intracavity laser spectrometer based on a neodymium laser with threshold
sensitivity to absorption 10–8 cm–1 and spectral resolution 0.035 cm–1 to study the absorption spectrum of D216O, H216O, and HD16O vapor. The high-temperature spectrum contains more than 450 absorption lines, 240 of which are assigned to the HDO isotopomer.
The absorption lines of HDO were identified and belong to nine vibrational transitions: 3ν2 +ν3, 2ν1 + 3ν2, 2ν1 + ν3, 4ν2 + ν3, 7ν2, ν1 + 2ν2 + ν3, ν1 + 5ν2, ν1 + 2ν2, and 3ν3 – ν2. 相似文献
2.
V. N. Bocharov A. P. Burtsev E. V. Dubrovskaya T. D. Kolomiitsova D. N. Shchepkin 《Optics and Spectroscopy》2010,108(4):533-543
IR spectra of the solution of SF6 molecules in liquid NF3 at 84 K have been recorded. In a solvent transmission window of 1500–1750 cm−1, two wide absorption bands with pronounced peaks in the high-frequency part are observed. The profile of these bands is explained
by the influence of the resonance dipole-dipole (RDD) interaction of the states of the simultaneous transition ν1(SF6) + ν3(NF3) and ν2(SF6) + ν3(NF3) with the states (ν1 + ν3) and (ν2 + ν3) of the SF6 molecules, respectively. The use of three isotopic modifications 32SF6, 33SF6, and 34SF6 has allowed us to vary the resonance detuning and thus to change the strength of the RDD interaction. With the liquid near
the melting point being represented as a close-packed cubic crystal, the profile was calculated and its spectral characteristics
were determined. The frequencies of the main peaks coincide with the experimental values accurate to the error. 相似文献
3.
The functions of the main indices of refraction n(ν) and absorption κ(ν) of uniaxial thin polyethylene terephthalate films
have been calculated by the experimental spectra of frustrated total reflection of s-and p-polarized radiation in the 700–760-cm−1 range. The κo(ν) maximum falls at the the 727-cm−1 frequency and the maximum of κe(ν) falls at the the 724-and 732-cm− 1 frequencies.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 756–759, November–December, 2005. 相似文献
4.
R.M. Mihalcea M.E. Webber D.S. Baer R.K. Hanson G.S. Feller W.B. Chapman 《Applied physics. B, Lasers and optics》1998,67(3):283-288
2 , H2O, N2O, and NH3 concentrations in various flowfields using absorption spectroscopy and extractive sampling techniques. An external-cavity
diode laser with a tuning range of 1.953–2.057 μm was used to record absorption lineshapes from measured transitions in the
CO2 4ν2
0+ν3, ν1+2ν2
0+ν3, and 2ν1+ν3 bands, H2O ν2+ν3and ν1+ν2 bands, N2O 2ν1+4ν2
0, ν2
1+2ν3, 3ν1+2ν2
0, and 4ν1 bands, and NH3ν1+ν4 and ν3+ν4 bands. Measured CO2, H2O, and N2O survey spectra were compared to calculations to verify the HITRAN96 database and used to determine optimum transitions for
species detection. Individual lineshape measurements were used to determine fundamental spectroscopic parameters including
the line strength, line-center frequency, and self-broadening coefficient of the probed transition. The results represent
the first measurements of CO2, H2O, N2O, and NH3 absorption near 2.0 μm using room-temperature near-IR diode lasers.
Received: 12 March 1998/Revised version: 7 May 1998 相似文献
5.
The preparation of pyridine functionalized TbF3 nanoparticles are described in this report. Synthesized nanoparticles were characterized using the TEM, UV/Vis, FTIR and
photoluminescence spectroscopy. TEM micrograph reveals the nanorod shaped, uniform in size with a particles size in the range
of 20–30 nm. FTIR spectrum shown characteristic absorption bands of pyridine and a small intensity band at 411 cm−1 corresponding metal nitrogen ν(Tb–N) bonding. Uv-vis spectrum shown the characteristic absorption transitions of Tb3+ ion. A strong emission transition at 540 nm (5D4 → 7F5) was observed on excite by visible light at 414 nm. 相似文献
6.
L. Ciaffoni B. L. Cummings W. Denzer R. Peverall S. R. Procter G. A. D. Ritchie 《Applied physics. B, Lasers and optics》2008,92(4):627-633
High resolution diode laser spectroscopy has been applied to the detection of hydrogen sulphide at ppm levels utilizing different
transitions within the region of the ν
1+ν
2+ν
3 and 2ν
1+ν
2 combination bands around 1.58 μm. Suitable lines in this spectral region have been identified, and absolute absorption cross
sections have been determined through single-pass absorption spectroscopy and confirmed in the Doppler linewidth regime using
cavity enhanced absorption spectroscopy (CEAS). The desire for a sensitive system potentially applicable to H2S sensing at atmospheric pressure has led to an investigation on suitable transitions using wavelength modulation spectroscopy
(WMS). The set-up sensitivity has been calculated as 1.73×10−8 cm−1 s1/2, and probing the strongest line at 1576.29 nm a minimum detectable concentration of 700 ppb under atmospheric conditions
has been achieved. Furthermore, pressure broadening coefficients for a variety of buffer gasses have been measured and correlated
to the intermolecular potentials governing the collision process; the H2S–H2S dimer well depth is estimated to be 7.06±0.09 kJ mol−1. 相似文献
7.
J. Cousin P. Masselin W. Chen D. Boucher S. Kassi D. Romanini P. Szriftgiser 《Applied physics. B, Lasers and optics》2006,83(2):261-266
Development of a continuous-wave tunable fiber laser-based spectrometer for applied spectroscopy is reported. Wide wavelength tunability of an erbium-doped fiber laser (EDFL) was investigated in the near-infrared region of 1543–1601 nm. Continuous mode-hop free fine frequency tuning has been accomplished by temperature tuning in conjunction with mechanical tuning. The overall spectroscopic performance of the EDFL was evaluated in terms of frequency tunability along with its suitability for molecular spectroscopy. High-resolution absorption spectra of acetylene (C2H2) were recorded near 1544 nm with a minimum measurable absorption coefficient of about 3.5×10-7 cm-1/Hz1/2 for direct absorption spectroscopy associated with a 100-m long multipass cell. Detections of C2H2 at different concentration levels were performed as well with high dynamic detection range varying from 100% purity to sub ppmv using cavity ring down spectroscopy. A 3σ-detection-limited minimum detectable concentration (MDC) of 400 ppbv has been obtained by using the transition line Pe(22) of the ν1+ν3+ν5
1(Πg)-ν5
1(Πu) hot band near 1543.92 nm with a detection bandwidth of 2.3 Hz. This corresponds to a minimum detectable absorption coefficient of 6.6×10-11 cm-1/Hz1/2. The sensitivity limit could be further improved by almost one order of magnitude (down to ∼60 ppbv) by use of the Pe(27) line of the ν1+ν3(Σu
+)-0(Σg
+)combination band near 1543.68 nm. PACS 42.55.Wd; 42.62.Fi; 07.57.Ty; 07.88.+y 相似文献
8.
O. S. Golubkova V. N. Bocharov A. P. Burtsev D. N. Shchepkin 《Optics and Spectroscopy》2011,111(3):357-366
We have obtained IR absorption spectra of a C2F6 gas and a C2F6 cryosolution in Xe (T = 163 K) in the fundamental and overtone ranges. We have interpreted 28 bands of 12C12CF6 and three bands of 13C12CF6. In the spectral ranges that correspond to vibrations that are combinations with ν1, ν7, and ν5, we observe multiplets, which we attribute to interactions of the type of Fermi resonances between the states ν1(A
1g
) ∼ ν6(A
1g
), ν7(E
g
) ∼ ν6 + ν11(E
g
) ∼ 2ν8(E
g
), ν5(A
2u
) ∼ ν8 + ν 11(A
2u
). We reveal an anomalous intensity distribution in the spectrum of an asymmetric isotopologue. For the basic and isotopic
configurations of perfluoroethane, we calculate the coefficients of shapes of vibrations and the intensities of absorption
bands. We reveal that the behavior of the groups 12CF3 and 13CF3 is indifferent to the excitation of doubly degenerate stretching vibrations ν7(E
g
) and ν10(Eu). 相似文献
9.
Fourier transform infrared spectroscopy studies have been conducted to investigate the interaction among components in a system
of high molecular weight polyvinylchloride (PVC)–lithium trifluoromethanesulfonate (LiCF3SO3) incorporated with different type of plasticizers, namely, ethylene carbonate (EC), propylene carbonate (PC), and dibutylphthalate
(DBP). Interaction between PVC and LiCF3SO3 was confirmed by C–H rocking mode at 1,255 cm−1 for PVC shift to 1,252 cm−1 in PVC–LiCF3SO3. The plasticizers’ carbonyl (C=O) oxygen atom which carries lone pair electrons interact with Li+ of LiCF3SO3 and methine hydrogen of PVC in LiCF3SO3–plasticizer system and PVC–plasticizer system, respectively. Changes in peaks assigned to 1,264 cm−1 (ν
as(SO3)), 1,033 cm−1 (ν
s(SO3)), 1,181 cm−1 (ν
as(CF3)), 1,230 cm−1 (ν
s(CF3)), 765 cm−1 (δ
s(CF3)), 644 cm−1 (δ
s(SO3)), 578 cm−1 (δ
as(CF3)), and 519 cm−1 (δ
as(SO3)) indicate the occurrence of complexation in the PVC–LiCF3SO3 system, LiCF3SO3–plasticizer system, and PVC–LiCF3SO3–plasticizer system. 相似文献
10.
Absolute spectral luminosity from an O2–O2(a)-H2O gas flow formed by a chemical singlet oxygen generator was measured at 600–800 and 1230–1310 nm wavelengths. The results
were used to determine the rate constants for O2(a, 0) + O2(a, 0) → O2(X, 0) + O2(X, 0) + hν (λ = 634 nm) and O2(a, 0) + O2(a, 0) → O2(X, 1) + O2(X, 0) + hν (λ = 703 nm) collision-induced emission ((6.72 ± 0.8) × 10−23 and (7.17 ± 0.8) × 10−23 cm3/s, respectively). 相似文献
11.
V. I. Starikov 《Optics and Spectroscopy》2011,110(3):340-350
The coefficients γ of broadening by self-pressure, and pressure of nitrogen, oxygen, and air are calculated for absorption
lines of the rotational band and for the ν2 band of the ozone molecule for temperatures 296, 252, and 212 K. The calculations are performed by the semiclassical method
using rectilinear and exact trajectories for interacting molecules. It is shown that the experimental data obtained for the
two bands at T = 296 K can be reconstructed better using different isotropic intermolecular interaction potentials. The experimental and
calculated broadening coefficients of ozone absorption lines for the rotational band and for the ν2 and ν1 + ν3 vibrational bands were used to determine the parameters of an analytical model, which permits one to calculate γ in a wide
range of rotational quantum numbers, 0 ≤ J ≤ 45, 0 ≤ K
a
≤ 20, and temperatures of 200–296 K. 相似文献
12.
A method for gas temperature measurements with a widely tunable laser diode is presented. The method involves rapidly switching
the laser frequency between two distantly spaced absorption lines chosen for optical thermometry. Direct absorption spectroscopy
using a single-mode VCSEL was employed to probe the R10 and R22 lines of the 2ν1+2ν2
0+ν3 combination band of CO2 near 6355.9 and 6363.7 cm-1 sequentially. A specially designed 0.5-m cryogenic gas cell was filled with 10 mbar CO2 at room temperature and cooled to 150 K with liquid N2. The VCSEL was modulated with a 10-kHz ramp superimposed on a 1-kHz square waveform to scan two 0.04 cm-1 intervals sequentially. The gas temperatures obtained with the VCSEL in the 150–300 K range are in a good agreement with
those derived from gas pressure ratios. The maximum relative error of temperature measurements using the VCSEL was ± 3%. A
compact VCSEL-based sensor can be developed for gas temperature and concentration measurements in the Martian atmosphere.
The method proposed can be used for many applications including in situ monitoring of combustion processes.
PACS 42.62.Fi; 42.55.Px; 39.30.+w 相似文献
13.
A. I. Reznikov S. Ya. Umanskii Yu. F. Chaikina 《Russian Journal of Physical Chemistry B, Focus on Physics》2010,4(2):203-209
Rate constants for electron-vibrational energy exchange Ar(3
P
2) + N2(X
1Σ
g
+, ν = 0) → Ar(1
S
0) + N2(C
3Π
u
, ν′), where ν′ = 0, 1, 2, were calculated. Calculations were performed taking into account the presence of a resonance in electron scattering
by N2(X
1Σ
g
+). As a result, the interaction of Ar(3
P
2) with N2(X
1Σ
g
+, ν = 0) was characterized by attraction and, in the end, intersection of electron-vibrational potential surfaces correlating
with Ar(3
P
2) + N2(X
1Σ
g
+, ν = 0) and Ar(1
S
0) + N2(C
3Π
u
, ν′) at interparticle distances of 2.5–3.5 ?. Exchange interaction at which electron-vibrational transitions in the region of
intersection of electron-vibrational transitions in the region of intersection of electron-vibrational potential surfaces
accompanied by spin exchange were induced was calculated by the asymptotic method. The rate constants determined at 300–600
K were on the order of 10−11−10−12 cm3/s and weakly increased as the temperature grew. Mainly the C
3Π
u
, ν′ = 0 state of the N2 molecule was populated. The calculation results were in satisfactory agreement with the experimental data obtained at 300
K. 相似文献
14.
M. V. Zagidullin 《Optics and Spectroscopy》2010,109(4):538-542
In the temperature range of T = 150–400 K, the dependence of spectral widths (cm−1) on temperature, 182 + 0.38(±0.01)T and 217 + 0.48(±0.01)T, respectively, has been obtained for dimole emission of O2(a, 0) + O2(a, 0) → O2(X, 1) + O2(X, 0) + hν (λ = 703 nm) and O2(a, 0) + O2(a, 0) → O2(X, 0) + O2(X, 0) + hν (λ = 634 nm). It was shown that the ratio of dimole emission rate constants does not depend on temperature in the range
of 150–400 K and is 1.06 ± 0.01. 相似文献
15.
Studies on the performances of silica aerogel electrodes for the application of supercapacitor 总被引:1,自引:0,他引:1
Silica aerogel (SiO2 aerogel) was prepared by sol–gel method from tetraethyl orthosilicate hydrolyzation and has been characterized by scanning
electron microscopy and N2 adsorption for its surface structure, surface area, and pore-size distribution. Constant current charge–discharge technique,
cyclic voltammetry, and electrochemical impedance spectrum were employed for its specific capacitance and equivalent series
resistance. The results showed that the maximum specific capacitance of SiO2 aerogel electrode in 1 M Et4NBF4/PC electrolyte was 62.5 F g−1. In addition, the SiO2 aerogel capacitor exhibits excellent long-term stability with no significant degradation after 500 charging and discharging
cycles. Therefore, the application of high surface area SiO2 aerogel as electrodes in supercapacitor devices is promising. 相似文献
16.
We have recorded the fluorescence excitation spectra of three heterocyclic compounds with a chain structure [BPO (2-phenyl-5-(4-diphenylyl)oxazole),
POPOP (1,4-di[2-(5-phenyloxazolyl)]benzene, and TOPOT (1,4-di[2-(5-n-tolyloxazolyl)]benzene] and the fluorescence spectra
of POPOP, under conditions where the molecules were cooled in an ultrasonic helium jet. A line structure is observed in the
spectra of POPOP and TOPOT; for the BPO molecules, whose configuration changes considerably during electronic excitation,
vibrational structure is apparent only in the low-frequency region of the excitation spectrum, and a diffuse spectrum is recorded
starting from ν
0
0
+ 200 cm−1. For all the compounds, in the spectra we recorded vibrations with frequencies up to 100 cm−1, arising due to the flexibility of the molecular structure. The rotational contours of the lines for the electronic and vibronic
transitions of the POPOP molecules (Trot = 10.5 K) and TOPOT molecules (Trot = 15 K) are structureless and bell-shaped. The degree of polarization of the fluorescence Pfl for the jet-cooled POPOP molecules for excitation of vibrations along the absorption band up to 2000 cm−1 above ν
0
0
is practically constant (∼8.4%) and matches Pfl for high-temperature vapors.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 728–734, November–December, 2006. 相似文献
17.
O.Yu. Nikiforova V.A. Kapitanov Yu.N. Ponomarev 《Applied physics. B, Lasers and optics》2008,90(2):263-268
Spectra measurements around 1.65 μm have revealed that spectral lines of ethylene are present in this range along with methane
spectral lines. Furthermore, the HITRAN database has no parameters of these ethylene lines. In particular, it was found that
several ethylene absorption lines are located near the methane feature often used for quantitative spectroscopy (R3 triplet
of the 2ν3 band). Ethylene can be present together with methane in the samples under study, perturbing the recorded spectrum of CH4. This perturbation by an interfering species can produce systematic errors in the derived CH4 concentration.
We have found in this work by numerical modelling that when measuring the methane concentration by a diode laser methane sensor
operating in the 6046–6048 cm-1 range, the systematic error on the retrieved CH4 concentration decreases, as a rule, when decreasing the width of the fitted spectral window. At equal concentrations of ethylene
and methane in the sample under study, the error on the concentration of CH4 determined by the correlation technique can reach 15%. When using the technique based on the 2nd or 3rd derivative of the
spectrum, interfering or impurity lines induce a systematic error on the derived CH4 concentration, which is less than 2%.
PACS 07.07.Df; 07.88.+y; 42.62.-b 相似文献
18.
The absorption of OH∗ chemiluminescence and laser-induced fluorescence (LIF) in the exhaust gas of confined premixed laminar CH4/air flames at atmospheric pressure was investigated. One flame was used as source and a second as absorber. OH LIF was excited
in the ν″=0→ν′=1 band of the A–X electronic system around ≈283 nm and spectrally resolved detected in the (0,0) and (1,1) vibrational bands
around 305–320 nm. For OH∗ chemiluminescence, spectrally resolved detection was performed in the wavelength range 280–340 nm. For an absorption path
of 54 mm and at T≈2000 K, signal trapping on the order of 10–40% was observed. Signal trapping was most pronounced in the (0,0) band, as expected
from the thermal population distribution of OH in the electronic ground state. The spectral distribution of the signals and
the wavelength dependence of the signal trapping are addressed in this paper. Implications from the results with respect to
detection strategies and chemiluminescence-based equivalence ratio measurements are discussed. 相似文献
19.
J. Cousin W. Chen D. Bigourd M. Fourmentin S. Kassi 《Applied physics. B, Lasers and optics》2009,97(4):919-929
We report on the development of a field deployable compact laser instrument tunable over ∼232 cm−1 from 3.16 to 3.41 μm (2932.5–3164.5 cm−1) for chemical species monitoring at the ppb-level. The laser instrument is based on widely tunable continuous-wave difference-frequency
generation (DFG), pumped by two telecom-grade fiber lasers. DFG power of ∼0.3 mW near 3.3 μm with a spectral purity of ∼3.3
MHz was achieved by using moderate pumping powers: 408 mW at 1062 nm and 636 mW at 1570 nm. Spectroscopic performance of the
developed DFG-based instrument was evaluated with direct absorption spectra of ethylene at 3.23 μm (∼3094.31 cm−1). Absorption spectra of vapor-phase benzene near 3.28 μm (∼3043.82 cm−1) were recorded with Doppler-limited resolution. Line intensities of the most intense absorption lines of the ν
12 band near 3043.8 cm−1 were determined to support development of sensitive mid-infrared trace gas detection of benzene vapor in the atmosphere.
Detection of benzene vapor in air at different concentration levels has been performed for the first time using multi-pass
cell enhanced direct absorption spectroscopy at ∼3.28 μm with a minimum detectable concentration of 50 ppb (1σ). 相似文献
20.
Glasses xLi2O–(50-x)(MoO3)2–50P2O5 with x = 10, 20, 30, and 40 mol% were prepared and their optical and electrical properties were investigated. Analysis of the IR
spectra revealed that the Li+ ions act as a glass modifier that enter the glass network by breaking up other linkages and creating non-bridging oxygens
in the network. The optical absorption edge of the glasses was measured for specimens in the form of thin blown films and
the optical absorption spectra of those were recorded in the range 200–800 nm. From the optical absorption edges studies,
the optical band gap (E
opt) and the Urbach energy (E
e) values have been evaluated by following the available semi-empirical theories. The linear variation of (αhν)1/2 with hν, is taken as evidence of indirect interband transitions. The E
opt values were found to decrease with increasing Li2O content by causing increase in the number of non-bridging oxygens in network. The Urbach tail analysis gives the width of
localized states between 0.48 and 0.74 eV. 相似文献