共查询到20条相似文献,搜索用时 31 毫秒
1.
The laser schlieren method has been used behind shock waves where the temperatures are 410–2400°K to measure the vibrational relaxation times for N2O and also for mixtures of N2O with CO, N2, and Ar. The vibrational relaxational times of N2O have been measured for collisions with these partners, and it has been found that the effectiveness of N2 in relaxation is close to that of N2O, whereas CO results in accelerated vibrational relaxation of N2O. A comparison is made with the available published data.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 3–8, November, 1984.We are indebted to V. V. Savkin for performing the mass spectral analyses. 相似文献
2.
M. Hammerich L. Vildrik-Sørensen H. de Vries J. Henningsen 《Applied physics. B, Lasers and optics》1991,53(3):170-179
A variable temperature photoacoustic cell has been constructed and tested by studying the interplay of CO2, H2O, and NH3 in synthetic smoke. Saturation effects for CO2 and NH3 have been modeled and compared with experiments, and results are obtained for the vibrational relaxation rate associated with NH3-H2O collisions. The cell has been used for studying the temperature dependence of self-broadening and N2 broadening of CO2 lines. The temperature dependence of the scattering rate is well described by a T
–n
law with n=0.77 in both cases. This result agrees with previous results obtained by tunable diode laser spectroscopy, but disagrees with results obtained by indirect methods.Supported by the Danish Science Research Council under grant no. 11-7777, and by FLS-airloq A/S 相似文献
3.
Z. V. Popović C. Thomsen M. Cardona R. Liu G. Stanišić W. König 《Zeitschrift für Physik B Condensed Matter》1988,72(1):13-16
We report both Raman and infrared reflectivity spectra of M2Cu2O5 (M=Y, Ho) at room temperature in the spectral range of 30–1000 cm–1.37 (31) ir and 18 (15) Raman active modes of Y2Cu2O5 (Ho2Cu2O5) are observed. A factor group analysis has been performed to identify the symmetries of the observed modes. Comparing the vibrational spectra of these compounds we conclude that the phonons above 300 cm–1 originate from the Cu–O vibrations and those under 300 cm–1 from M–O vibrations.Alexander von Humboldt Foundation fellow 相似文献
4.
Liyun Zhong Jiye Cai Yi Liu Honggao Tang Yuping Sun Jiaju Du 《International Journal of Infrared and Millimeter Waves》1991,12(3):239-249
In this paper we study the room-temperature infrared transmission spectra (400–1600cm–1) and far-infrared diffuse reflection spectra (50–450cm–1) in Pb-doped Bi–Sr–Ca–Cu–O (2223) single phase (Tc=107k, sp1), multiphase (Tc=110k, sp2) and nonsuperconducting samples (sp3). The spectral features in superconductor are totally different from those in nonsuperconductor, which show the different crystal structure. The correlation existing between a factor group analysis of the phonons in (2223) and (2212) compounds affords a tentative assignment of ir-active modes in Pb-doped (2223) single phase by comparison with reported data in (2212) materials. The Cu–O stretching Eu vibration (605cm–1) of CuO2 layers is the characteristic vibrational mode related perovskitelike crystal structures. Two phonon coupling effect emerges in the infrared transmission spectra in Pb-doped superconductor. The Ca–O vibration A2u (254cm–1) might be related to superconductivity of Bi-based family. 相似文献
5.
Robert A. Toth 《Journal of Molecular Spectroscopy》1998,190(2):379-396
This study involves measurements of H216O, H217O, and H218O vapor spectra for the region between 590 and 2582 cm−1. The parameters derived from the data include line positions, energy levels, and linestrengths. The study involves high-resolution line-position measurements with samples at room temperature in the (000)–(000), (010)–(010), and (010)–(000) bands. The experimental frequencies were used along with microwave, far-infrared, and hot water emission measurements in an analysis to obtain high-accuracy rotational energy level values in the (000), and (010) vibrational states of H216O forJ≤ 20. The experimental linestrengths were fitted by least squares to a model in which the dipole moment was represented as a series expansion containing up to 19 dipole moment matrix elements. The measurements in this work were more extensive than reported in prior studies by this author for the (010)–(000) band. 相似文献
6.
The solid neon matrix isolated spectrum of CO2 are recorded in the 2–5 μm region. Natural and 13C or 18O enriched CO2 samples were used and the nν1 + ν3 (n = 0, 1, 2) series bands of different CO2 isotopologues have been observed. The solid neon matrix shift due to Fermi-resonance of bands within the same vibrational polyad is analyzed. 相似文献
7.
We report the experimental rotational Raman spectra of H2O, and of a mixture of D2O and HDO in the vapor phase at room temperature, and their interpretation in terms of rotational–vibrational energies, wavefunctions, and transition moments of the molecular polarizability. These transition moments are based on high-level ab initio calculations of the wavelength dependent polarizability surface, and on wavefunctions where the rotational–vibrational coupling is considered in detail. As a byproduct of this analysis several tables have been compiled including scattering strengths and assignments for individual rotational transitions of the three species. From these tables the rotational Raman spectra can be simulated over the range of temperatures up to 2000 K for H2O, and up to 300 K for D2O and HDO. 相似文献
8.
The vibrational kinetics of CW CO2 lasers has been analyzed within the framework of a temperature model. The necessity of taking into account the coupling of the vibrational modes of the CO2 molecule in determining the occupation numbers and the store of vibrational energy in individual modes is shown. Expressions that connect vibrational temperatures with the rates of excitation and relaxation of the lower vibrational levels of modes have been obtained. The ratios between the vibrational temperatures on selective excitation of the 00° 1 level and on excitation of CO2 molecules in an electric discharge as well as the character of the dependences of vibrational temperatures on the pumping-energy value are discussed.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 1, pp. 72–79, January–February, 2005. 相似文献
9.
A method is described to compute the centrifugal constants from the first and second order energy moments. Presented as an illustration is a computation of the centrifugal constants of the H2O molecule for the 000 vibrational state; conditions proposed in [2] were imposed on the parameters of the unitary transformation; the centrifugal constants obtained under such conditions reproduce the spectrum to 0.1 cm–1 accuracy.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 80–84, August, 1973. 相似文献
10.
Z. Zelinger T. Amano V. Ahrens S. Brünken F. Lewen H.S.P. Müller G. Winnewisser 《Journal of Molecular Spectroscopy》2003,220(2):223-233
Measurements of the rotational spectrum of HCN in excited vibrational states have been extended to higher-J values. The transitions reach J=8←7 around 710 GHz for most vibrational states studied in this investigation and J=22←21 near 2 THz for the (020) and (030) vibrational states. Using a pure sample of gaseous HCN at 350 K, selected states up to one quantum in the C–H stretching vibration at 3311.5 cm−1 have been investigated. Even transitions having two quanta in the C–H stretch could be studied employing a glow discharge in a gas mixture of CH4 and N2. Molecular constants in 13 vibrational states have been obtained, several of which have been studied for the first time by rotational spectroscopy. The vibrational temperature in the discharge system is found to be about 1500 K for the stretching vibrational modes and about 600 K for the bending states. 相似文献
11.
This paper reports the assignment of the rotational spectra of the m = 0 and 1 states of 13CC5H6-H2O and C6H5D-H2O dimers. The m = 1 progression was not identified or assigned for both 13CC5H6-H2O and C6H5D-H2O in the earlier work, though for the symmetric isotopomers (C6H6-H2O/D2O/H218O), they were identified [H.S. Gutowsky, T. Emilsson, E. Arunan, J. Chem. Phys. 99 (1993) 4883]. The m = 1 transitions for 13CC5H6-H2O and C6H5D-H2O were split into two, unlike that of the parent C6H6-H2O isotopomer. The splitting varied, somewhat randomly, with quantum numbers J and K. The m = 0 lines of 13CC5H6-H2O had significant overlap with the m = 1 lines of the parent isotopomer, clouding proper assignment, and leading to an rms deviation of about 200 kHz in the earlier work. The general semi-rigid molecular Hamiltonian coupled to an internal rotor, described recently by Duan et al. [Y.B. Duan, H.M. Zhang, K. Takagi, J. Chem. Phys. 104 (1996) 3914], is used in this work to assign both m = 0 and 1 states of 13CC5H6-H2O and C6H5D-H2O dimers. Consequently, the m = 0 fits for 13CC5H6-H2O/D2O have an rms deviation of only 4/7 kHz, comparable to experimental uncertainties. The fits for m = 1 transitions for 13CC5H6-H2O and C6H5D-H2O dimers have an rms deviation of about 200 kHz. However, it is of the same order of magnitude as that of the m = 1 state of the parent C6H6-H2O dimer. The A rotational constants determined from the m = 0 fits for both 13CC5H6-H2O and 13CC5H6-D2O isotopomers are identical and very close to the C rotational constant for 13CC5H6. This provides a direct experimental determination for the C rotational constant of 13CC5H6, which has a negligible dipole moment. 相似文献
12.
J. Yu W.T. Jin Y. Zhao H. Zhang 《Physica C: Superconductivity and its Applications》2009,469(15-20):967-969
The Pr content dependence of the bond lengths of Y–Cu, Y–O, O–O, Cu–O, Ba–Cu and Ba–O in PrBa2Cu3Oy are analyzed and discussed in detail. The different valence bonds can be divided into two groups: stable bonds and unstable bonds. Since the bond lengths and angles between every two ions among O2, Cu2 and O3 are very stable, we conclude that the three ions form an unchangeable triangle when the Pr doping changes. The triangle is called “fixed triangle”. This “fixed triangle” can slightly rotate around the Cu2 ions. It is just this rotation that leads to the unstable bonds. As the increase of the Pr content, the bond lengths between the two Cu(2)–O planes becomes larger and larger, the Cu(2)–O planes bend towards the Ba–O plane. The bonds lengths between the Cu(2)–O and Ba–O planes vary oppositely from those of Cu(2)–O, and become shorter and shorter. These changes connected with the superconductivity are discussed. 相似文献
13.
We have investigated the luminescence of uranyl nitrate molecules on the surface of powdery SiO2 upon excitation by UV light (PhL) and hydrogen atoms (radical-recombination luminescence (RRL)). It has been found that the PhL and RRL spectra have a clearly defined vibrational structure. The luminescence peaks of the adsorbed UO2
2– ion are characterized by a systematic longwave shift from the same peaks of crystalline uranyl nitrate (by 230–430 cm–1 at 130 K). Moreover, in the adsorption centers the vibration frequencies of UO2
2– are 20–80 cm smaller than in crystalline salt and the RRL bands are 150–350 cm–1 (130 K) wider than the corresponding PhL bands. 相似文献
14.
Takashi Imajo Yuki Kobayashi Yoshihiro Nakashima Keiichi Tanaka Takehiko Tanaka 《Journal of Molecular Spectroscopy》2005,230(2):139-148
Ultraviolet emission spectra of the TiF radical in the 407 nm region have been observed at a resolution of 0.04 cm−1 using a Fourier transform spectrometer. A new electronic assignment of 4Γ–X4Φ has been proposed. Rotational analysis has been obtained for the 0–0 and 1–1 vibrational bands of the 4Γ5/2–X4Φ3/2, 4Γ9/2–X4Φ7/2, and 4Γ11/2–X4Φ9/2 subbands and the 0–0 band of 4Γ7/2–X4Φ5/2. The lower state rotational and centrifugal distortion constants are consistent with the previous results [J. Mol. Spectrosc. 184 (1997) 186; J. Chem. Phys. 119 (2003) 9496], to the conformation that the lower state of the 407 nm band is the 4Φ ground electronic state. Rough estimates of the vibrational interval ΔG(1/2) and the spin–orbit coupling constant A in the 4Γ state were also obtained. 相似文献
15.
A. Perrin J.-M. Flaud A. Valentin C. Camy-Peyret H. Gbaguidi 《Journal of Molecular Spectroscopy》2000,200(2)
Using 0.002 cm−1 resolution Fourier transform absorption spectra of an 17O-enriched ozone sample, an extensive analysis of the ν3 band together with a partial identification of the ν1 band of the 17O16O17O isotopomer of ozone has been performed for the first time. As for other C2v-type ozone isotopomers [J.-M. Flaud and R. Bacis, Spectrochim. Acta, Part A 54, 3–16 (1998)], the (001) rotational levels are involved in a Coriolis-type resonance with the levels of the (100) vibrational state. The experimental rotational levels of the (001) and (100) vibrational states have been satisfactorily reproduced using a Hamiltonian matrix which takes into account the observed rovibrational resonances. In this way precise vibrational energies and rotational and coupling constants were deduced and the following band centers ν0(ν3) = 1030.0946 cm−1 and ν0(ν1) = 1086.7490 cm−1 were obtained for the ν3 and ν1 bands, respectively. 相似文献
16.
The IR spectra and polarization Raman spectra of Kal(SO4)2·12(H2O) and Kal(SO4)2·12[H2O)0.3(D2O)0.7] crystals at 93 K and room temperature have been obtained experimentally. The vibrational spectra of structural elements of potassium alum — the complexes [Al(H2O)6
3+ and [Al(D2O)6]3+ — have been calculated. The vibrational spectra have been interpreted based on the calculation and factor-group analysis data. The spectral data obtained point to the fact that, in the crystals considered, the sulfate ions are partially disordered and there exist two crystallographically different types of water molecules. 相似文献
17.
A decaying weakly ionized helium plasma [ne=(0.2–1.1)·1011 cm–3, p=(40–70) mm Hg] was studied experimentally. It is shown that the experimental time dependences of the intensities of atomic lines and molecular bands in the afterglow phase can be explained if the vibrational kinetics of He2
+ ions is included in the analysis. Analysis of the measurements shows that for ne 1011 cm–3 and Na 1018 cm–3 deexcitation of He2
+ ions occurs primarily as a result of inelastic collisions with helium atoms. Based on the experimental data, an approximate value was obtained for the rate constants of the vibrational relaxation of molecular helium ions 10–16 cm3/sec. These results are used for making a qualitative analysis of the distribution of He2
+ ions over the vibrational states in the discharge phase.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 88–96, November, 1986. 相似文献
18.
Carbon dioxide (CO2) trace gas detection based on quartz enhanced photoacoustic spectroscopy (QEPAS) using a distributed feedback diode laser operating at λ=2 μm is performed, with a primary purpose of studying vibrational relaxation processes in the CO2-N2-H2O system. A simple model is developed and used to explain the experimentally observed dependence of amplitude and phase of the photoacoustic signal on pressure and gas humidity. A (1σ) sensitivity of 110 parts-per-million (with a 1 s lock-in time constant) was obtained for CO2 concentrations measured in humid gas samples. PACS 07.07.Df; 42.62.Fi; 82.80.Kq; 42.55.Px 相似文献
19.
A chemical H2–F2 laser (oscillator and amplifier) initiated by means of IR radiative excitation of vibrational levels of HF molecules is studied under the conditions of development of a thermal-branched chain reaction caused by thermal dissociation of gaseous additions to the laser mixture. It is shown that, using F2SO3 addition at a partial pressure of 40 Torr, an H2–F2 laser with a mixture pressure of 1~bar initiated by a pulsed hydrogen fluorine laser can provide an output exceeding 120–200 J/liter in 20–50 ns laser pulses. 相似文献
20.
T. Dreier U. Wellhausen J. Wolfrum G. Marowsky 《Applied physics. B, Lasers and optics》1982,29(1):31-36
Coherent anti-Stokes Raman spectroscopy (CARS) was used to measure the vibrational temperature of microwave-excited nitrogen in a N2–CO–He mixture. CARS spectra, originating from the N2-vibrational levelsv=0 up tov=3, have been recorded by both narrowband scanning of the resonance region as well as by broadband OSA detection. For the microwave-excited N2 molecules a vibrational temperatureT
v
(N
2 = (2130±110K) and a lower limit of detection forN
2(v = 3) = 1.2 x 1015 cm–3 was established. The CARS results were independently confirmed by simultaneously recorded and spectrally resolved CO infrared fluorescence studies. 相似文献