首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The A′1Π-X1Σ+ near infrared system of strontium oxide (SrO) was observed at high spectral resolution by measuring the chemiluminescence from a Broida flow reactor using a Fourier transform spectrometer. In total, 32 bands from , , were measured within the spectral region at a resolution of . Vibrational levels of the upper state were observed up to vA=4, and more than 5600 rotational lines were assigned. Incorporating previously published high resolution data for the A1Σ+-X1Σ+ system, a global fit to both data sets yields improved Dunham constants for the ground state and for the lower vibrational levels (vA=0, 1, and 2) of the A′1Π state. Because perturbations arising from interactions with the b3Σ+ and A1Σ+ states affect the higher vibrational levels of the A′1Π state more strongly, levels vA=3 and 4 were represented by effective band constants in the fits. RKR potentials for the X1Σ+,A′1Π, and b3Σ+ states have been generated utilizing all the available data, Franck-Condon factors have been calculated for the A′1Π-X1Σ+ system, and A′1Π∼b3Σ+ and A′1Π∼A1Σ+ perturbations are discussed.  相似文献   

2.
The millimeter- and submillimeter-wave spectra of AuCl and AuBr in the X1Σ+ states were observed by employing a source-modulated microwave spectrometer. The AuCl and AuBr molecules were, respectively, generated in a free space cell by a d.c. glow discharge in Cl2 and Br2 with Ar. The gold atoms were supplied by the sputtering reaction from a gold sheet placed on the inner surface of a stainless-steel cathode. Rotational transitions of , , , and in highly excited vibrational states as well as in the ground vibrational states were measured in the region between 189 and 314 GHz. The transition frequencies were analyzed by a least-squares method using a combined-isotopomer Dunham-type term energy expression. The potential constants of gold halides obtained were compared with those of copper and silver halides.  相似文献   

3.
4.
Fourier-transform intracavity laser absorption spectroscopy allowed five 12C13CH2 Σ++ bands, all from the ground state, to be identified in the 0.83 μm range. Their rotational analysis was performed and rotational constants are provided. Three of these bands, with origins at 11616.9684(18), 11737.2356(14), and 11761.0322(23) cm−1, have never been reported before. Their upper states are assigned to , respectively.  相似文献   

5.
6.
The laser excitation spectrum of the 288 nm band system of FeCl2, formed in a free-jet expansion, has been recorded at a rotational temperature of approximately 10 K. Vibronic transitions are observed from the ground state to two close-lying excited electronic states that differ in inversion (g, u) parity. Two extensive progressions in the symmetric stretching vibration have been identified, referred to as Progressions A and B. The main features of Progression A, which is based on the band, are allowed transitions to the excited electronic state of ungerade symmetry. Progression B is built on the band and consists of vibronically induced transitions to the gerade excited state. A substantial decrease in the symmetric stretching vibrational wavenumber is observed on excitation . Local perturbations are found to cause relative shifts between the different isotopomers. Several vibronic bands have been recorded and analysed at rotational resolution for the three isotopomers Fe35Cl2, Fe35Cl37Cl, and Fe37Cl2 in natural abundance. All bands show perpendicular rotational structure of a linear molecule, and have been unambiguously assigned to a Ω = 5-4 transition, consistent with the inverted 5Δg ground state predicted by ab initio and DFT calculations. The zero-point averaged FeCl bond length is determined to be in the upper and lower electronic states. The results show that the molecule is linear in both states.  相似文献   

7.
The absorption spectra of jet-cooled AsH2 radicals were recorded in the wavelength range of 435-510 nm by cavity ringdown spectroscopy. The AsH2 radicals were produced by pulsed DC discharge in a molecular beam of a mixture of AsH3, SF6, and argon. Seven vibronic bands with fine rotational structures have been identified and assigned as the , , and (n = 1-3) bands of the electronic transition. Based on the previous studies of AsH2 radical, rotational assignments and rotational term values for each band were obtained, and the molecular parameters including vibrational constants, rotational constants, centrifugal distortion constants, and spin-rotation interaction constants were also determined.  相似文献   

8.
The gerade autoionizing Rydberg states of Ne2 have been studied in the range 162 000-172 000 cm−1 by 1 + 1′ resonant two-photon excitation from the Ne2 X ground state via different vibrational levels of the Ne2 C state. A rotationally resolved part of the spectrum allowed the determination of the potential energy functions of two states of 1g and characters in the vicinity of the Ne(2p61S0) + Ne (2p54p′) dissociation limit. The presence of maxima in these potential energy functions is interpreted as originating from a repulsive interaction between the Rydberg electron and the neutral atom.  相似文献   

9.
Ab initio calculations of the electronic dipole moment components for the and electronic states and the electronic transition moment for the - transition of H2O+ have been carried out. Parameterized analytical functions have been fitted through the computed ab initio data points, and the resulting dipole moment and transition moment surfaces have been used, along with potential energy surfaces derived from the ab initio results of Brommer et al. [J. Chem. Phys. 98 (1993) 5222], to simulate H2O+ spectra and to generate an extensive set of vibronic transition moments for the and band systems of H2O+. The work is made with the dual purpose of facilitating further assignments of high-resolution spectra [J. Mol. Spectrosc. 219 (2003) 258] and of allowing cometary spectra of H2O+ to be simulated [Ap. J. 574 (2002) L183].  相似文献   

10.
Overtone absorption lines of 12C16O2 have been examined by using a tunable diode laser (TDL) spectrometer in the region around . The spectrometer sources are commercially available double heterostructure InGaAlAs TDLs operating in the “free-running” mode, which allowed the detection of the line positions within . The observed carbon dioxide absorption lines belong to the ν1+5ν3 ro-vibrational band with rotational quantum number J up to 48. The minimum absorbance detected by the spectrometer (?5×10-6) permitted to observe the weakest lines having the absorption cross section of the order of .  相似文献   

11.
We have irradiated SrTiO3 single crystal with 3 MeV-proton (H+) beam and found that blue -, green - and infrared - frequency photoluminescence (PL) are induced simultaneously at room temperature. TEM and EELS analyses show that an oxygen-deficient amorphous layer is formed at the crystal surface by the proton irradiation. Possible origin of the PL-effect is discussed.  相似文献   

12.
Microwave study of the rotational transitions of oxygen molecule in its electronic and vibrational ground states is reported. Eight transitions belonging to N=3-1, N=5-3, and N=7-5 groups were investigated. Central line frequencies and pressure broadening parameters for O2 and N2 as perturbers were determined. The highest frequency of measured transition (N,J)=(7,6)-(5,6) has been 1.12 THz. Spectrometer with backward wave oscillator (BWO) and acoustic detector (RAD) was used. Since this experiment has more than doubled the number of previously measured rotational lines of oxygen molecule and better accuracy was achieved, the fitting of new set of rotational transition frequencies has been performed and new more accurate molecular constants for in , v=0 state have been obtained.  相似文献   

13.
The emission spectrum of VCl has been investigated at high resolution in the 3000-19 400 cm−1 region using a Fourier transform spectrometer. The bands were excited in a high temperature carbon tube furnace by the reaction of vanadium metal vapor and a trace of BCl3 as well as in a microwave discharge lamp by the reaction of VOCl3 vapor with active nitrogen. The spectra were recorded using the Fourier transform spectrometer associated with the McMath-Pierce telescope of the National Solar Observatory at Kitt Peak. The analysis of the system of VCl (previously labeled as ) has been extended by analyzing the rotational structure of some additional bands. A rotational analysis of the , , and subbands of the 0-2, 0-1, 0-0, and 1-0 bands, and the subband of the 0-1 and 0-0 bands has been obtained and molecular constants have been extracted. The subband was not identified in any of the assigned bands. The spectroscopic properties of the low-lying electronic states of VCl have been predicted by CASSCF/CMRCI ab initio calculations and the experimental assignments are supported by the ab initio results.  相似文献   

14.
A new 3Π-3Σ band was observed in a discharge plasma of the nitrogen molecule and helium using near-infrared diode laser kinetic spectroscopy. All the lines in this band exhibited line broadening of more than 0.1 cm−1. Rotational analysis revealed that the lower state of the transition was the state of N2, which had already been studied in the D3Σ-E3Σ band. The term value and rotational constant suggested that the upper state is the G3Πu Rydberg state with an electron configuration of (N2+:X2Σ core)(3pπu). The line broadening is attributed to predissociation through a homogeneous interaction with a repulsive Πu state.  相似文献   

15.
Fourier transform emission spectra of CoCl were obtained with a tube furnace-DC discharge source in the 450-500 nm spectral region. In addition to observing two different band systems, which were assigned as [20.7] and [21.3] by Adam et al. [J. Mol. Spectrosc. 212 (2002) 111], we obtained data for additional sub-bands and vibrational levels. In contrast to the previous work, intense Q branches are seen in the [21.3]- bands which indicate that these bands are likely ΔΛ≠0 transitions. The equilibrium rotational constant Be for the ground state is 0.1801104(28) cm−1, the equilibrium bond length is 2.065122(16) Å and ΔG1/2 is 430.418(5) cm−1.  相似文献   

16.
OH-doped KBr polycrystals were colored electrolytically by using a pointed cathode and a flat anode. Characteristic O, OH, U, Cu+ and absorption peaks were observed in resolved absorption spectrum of uncolored polycrystals. Herein the position of the absorption peak at room temperature was determined by using a Mollwo-Ivey plot. Characteristic V2, V3, Cu+, , I2 and F spectral bands were observed in Kubelka-Munk functions of colored polycrystals. Current-time curve for electrolytic coloration of an OH-doped KBr polycrystal and its relationship with electrolytic coloration process were given. Formation and conversion of color centers were explained.  相似文献   

17.
Infrared spectrum of the cobalt carbonyl radical CoCO produced by the 193 nm excimer laser photolysis of cobalt tricarbonyl nitrosyl Co(CO)3NO was observed by time-resolved diode laser spectroscopy. More than 600 lines were identified as belonging to the ν1 (C-O stretch) fundamental band, consisting of the Ω=5/2 and 3/2 subbands, and the associated hot bands , , , and . The 2Δi electronic ground state of CoCO was experimentally confirmed. The ν1 band origins are 1974.172582(93) cm−1 and 1973.53178(14) cm−1 for the Ω=5/2 and 3/2 subbands, respectively. The rotational constant in the ground state was determined as B0=4427.146(50) MHz. The centrifugal distortion constant D0=1.1243(68) kHz was obtained for the Ω=5/2 substate of the ground state. The equilibrium rotational constant Be=4435.44(14) MHz was derived, together with the vibration-rotation interaction constants.  相似文献   

18.
The vibrational structure of the electronic state of C3 in the region 26 000-30 775 cm−1 has been re-examined, using laser excitation spectra of jet-cooled molecules. Rotational constants and vibrational energies have been determined for over 60 previously-unreported vibronic levels; a number of other levels have been re-assigned. The vibrational structure is complicated by interactions between levels of the upper and lower Born-Oppenheimer components of the state, and by the effects of the double minimum potential in the Q3 coordinate, recognized by Izuha and Yamanouchi [16]. The present work shows that there is also strong anharmonic resonance between the overtones of the ν1 and ν3 vibrations. For instance, the levels 2 1+ 1 and 0 1 + 3 are nearly degenerate in zero order, but as a result of the resonance they give rise to two levels 139 cm−1 apart, centered about the expected position of the 2 1+ 1 level. With these irregularities recognized, every observed vibrational level up to 30 000 cm−1 (a vibrational energy of over 5000 cm−1) can now be assigned. A vibronic level at 30181.4 cm−1, which has a much lower B′ rotational constant than nearby levels of the state, possibly represents the onset of vibronic perturbations by the electronic state; this state is so far unknown, but is predicted by the ab initio calculations of Ahmed et al. [36].  相似文献   

19.
In a recent theoretical paper, vibrational frequencies were reported for CBrCl in the and à states. These values agree well with our previously published experimental frequencies, except in the case of , where the theoretical value of 968.3 cm−1 is significantly higher than the experimental value of 712.6 cm−1. This discrepancy prompted a re-examination of the assignments for transitions involving ν1 in the laser induced fluorescence spectrum. If the progression ν1 + 2 has the assignment of n reduced by 1 (the origin is not observed), a new experimental value of results. The close accord with the theoretical value lends weight to this re-assignment. Consequently we propose that the experimental frequency be changed to .  相似文献   

20.
Using third harmonics of LiF:F2+ tunable color center laser excitation and selective fluorescence detection the temperature and concentration dependencies of fluorescence decay curves of the high-lying manifold of the Nd3+ ion were measured in CeF3 crystals. As a result the temperature dependence of energy transfer kinetics from the manifold of the Nd3+ donor ions to the manifold of the acceptor Ce3+ ions in the ordered practically 100% filled crystal lattice was determined for 13-. Based on the temperature dependence the mechanisms and the channels of the Nd→Ce nonradiative energy transfer have been recognized. The net growth of the resonance Nd→Ce energy transfer rate in the temperature range from 25 to is found to be almost 3 orders of magnitude from 9.0×104 to .In a crystal a significant contribution of the Nd→Nd resonance energy transfer to the manifold quenching is found for 20- and its channel and mechanism are suggested.Discussion of the possibility of subpicosecond and picosecond nonradiative energy transfer in rare-earth doped laser crystals is provided.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号