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1.
The method of Lamb dip spectroscopy in Stark tuned molecular gases is discussed and applied to the experimental assignment of methyl alcohol infrared transitions in the 5 C–O stretch band. Theoretical expressions for Stark Lamb dip patterns are derived for P, Q and R-branch transitions. Stark tuning results and transition quantum number assignments are presented for several 10m transitions, along with measured values of resonant frequencies, absorption coefficients and pressure broadening coefficients.Work supported by the Army Research Office, Durham, and the National Science Foundation.  相似文献   

2.
Using a CO laser, laser Stark resonance spectra were measured for the CN stretching fundamentals (the 0001-0000 bands) of D12C14N and D12C15N near 1925 cm?1. Laser Stark resonances were also measured for the hot band 0111-0110 of D12C14N. In addition to accurately determining the band centers, dipole moments are given for the different vibrational states involved.  相似文献   

3.
Laser Stark spectra of carbonyl sulfide have been measured with parallel and perpendicular polarization of a 9.4 μm band CO2 laser with the Stark field up to 90 kV/cm. Components of the P(2) and R(1) transitions of the 0310–0110 band and those of the P(1) transition of the 0400–0200 band for 16O12C32S have been analyzed. Band origins, 1052.9446 (4) cm?1 for 0310–0110 and 1057.7860 (5) cm?1 for 0400–0200, and dipole moments, 0.7035 (16) D for 0110 and 0.6810 (24) D for 031P, are obtained.  相似文献   

4.
We demonstrate phase-coherent Stark effects from a radiofrequency E field at twice the NMR frequency (2ω(0)) of (69)Ga in GaAs. The 2ω(0) phase (?(E)) selects component responses from the nuclear quadrupole Hamiltonian (H(Q)). This is possible by synchronizing few-μs 2ω(0) pulses with an NMR line-narrowing sequence, which averages the Stark interaction to dominate spectra on a background with 10(3)× enhanced resolution. Spectra vs ?(E) reveal relative sizes of tensorial factors in H(Q). Comparative modeling and numerical simulations evaluate spectral features unexplained by average Hamiltonian theory, and suggest improvements for quantitative calibration of individual response components. Application of this approach to bulk samples is of value to define Stark responses that may later be used to interrogate the internal electrostatics of structured samples.  相似文献   

5.
We present a new technique for selectively populating excited states which are inaccessible by dipole excitation from the ground state. The method uses a static electric field to introduce a component of a dipole-allowed state into the state of interest. We have applied the method to cesium to measure lifetimes and a Stark mixing coefficient. The results are τ(62D52)=64(2) ns, τ(72D52)=92.5(15) ns, and <62D52|;ez |72P32>/(E7P?E6D)=0.7(3)×10?3 where is in kV/cm. 141  相似文献   

6.
C. T. Lin 《光谱学快报》2013,46(9):615-631
A potentially useful scheme for photoselective isotope enrichment is presented. The selective laser excitation step is accomplished by utilizing the Stark effect to shift molecular transitions into resonance with laser frequencies. The method is demonstrated for isotope separation of 13C, 15N and 2H. Laser Stark spectroscopy can sensitively detect as few as 109 molecules in the optical path, thus the isotopic separation can be achieved from industrial sample mixtures containing natural abundances. A comparison of the isotopic enrichment efficiency using the present method of “exact” resonance and the previously used method of “near” resonance excitation is also given.  相似文献   

7.
The far-infrared laser Stark spectrum of 1,1 difluoroethylene (H2C=CF2) has been investigated with the 311 m line of the hydrogen cyanide (HCN) laser. Numerous families of absorption lines have been observed for both parallel and perpendicular polarizations up to 60 000 V/cm. Three families of resonances have been identified as J(Ka,Kc) = 41(35,7) 40(33,8), 40(36,5) 39(34,6) and 43(35,8) 42(33,9). The Stark shift for the first two transitions can be adequately explained by quasi-first-order calculations, whereas the Stark shift for the third transition requires second-order corrections. The zero-field frequencies for these transitions have been experimentally determined and are reported with fractional uncertainties up to a few parts in 106.  相似文献   

8.
9.
The CO2 laser Stark spectrum of deuterated fluoroacetylene was identified with the aid of the double-resonance technique for the ν3, ν3 + ν5 ? ν5, ν3 + ν4 ? ν4, ν3 + 2ν5 ? 2ν5, and ν3 + ν4 + ν5 ? ν4 ? ν5 vibrational bands. Laser microwave double-resonance signals were observed in the presence of the Stark field. From the analysis of the double-resonance signals precise values of the dipole moment were obtained for 10 vibrational states, in Debye, with the uncertainties in parentheses: ground, 0.73292(22); ν5, 0.75656(17); ν4, 0.68412(24); 2ν5+), 0.78063(21); ν4 + ν5+ or Σ?), 0.70698(19); ν3, 0.75772(30); ν3 + ν5, 0.78270(18); ν3 + ν4, 0.70822(17); ν3 + 2ν5+), 0.80808(25); ν3 + ν4 + ν5+ or Σ?), 0.73329(17). The band origins were determined (in cm?1); ν3, 1045.9242(8); ν3 + ν5 ? ν5, 1049.6441(8); ν3 + ν4 ? ν4, 1047.8700(8); ν3 + 2ν5 ? 2ν5++), 1053.0374(8); ν3 + ν4 + ν5 ? ν4 ? ν5++ or Σ??), 1051.5040(8).  相似文献   

10.
The CO2 laser Stark spectrum of fluoroacetylene was identified for the ν3, ν3 + ν4 ? ν4, and ν3 + ν5 ? ν5 vibrational bands. The origins of these bands were precisely determined (±0.0003 cm?1) to be 1061.4452, 1059.0639, and 1064.6960 cm?1. A CO2 laser microwave double resonance experiment in the presence of the Stark field is described. This technique was applied to assignment of the Stark spectrum, calibration of the Stark electrode spacing, and precise determination (±0.0003 D) of dipole moment. The dipole moments of the HCCF molecule in the ground, ν3, ν4, ν5, ν3 + ν4, and ν3 + ν5 vibrational states are 0.7207, 0.7447, 0.6557, 0.7441, 0.6769, and 0.7689 D.  相似文献   

11.
12.
13.
The effects of a radio frequency electric field modulation on Stark tuned level crossings and saturated absorptions at 10 µm are investigated and compared with the dressed molecule theory. Applications are made to rotational quantum state assignment and electric dipole measurements. The dipole moments of NH2D in the ground and ν2 = 1 state are measured to be   相似文献   

14.
Stark spectroscopy, which is well established for probing transitions between the ground and excited states of many material classes, is extended to transitions between transient excited states. To this end, it is combined with femtosecond pump-probe spectroscopy on a conjugated polymer with appropriately introduced traps which harvest excitation energy and build up a sufficient excited state population. The results indicate a significant difference in the effective dipole moments between two short lived excited states.  相似文献   

15.
High resolution Stark spectra have been observed for the pure rotation transition of D2O which lies very close to the 337 µm HCN maser emission. The assignment of the transition is confirmed as 624-615 and the frequency separation as approximately 370 Mhz on the low frequency side of the maser emission.

Stark spectra have been observed for several other gases but due to the large number of Stark components complete resolution was not achieved. However, it is shown that even in these cases some information can be gained about the type of pure rotation transition responsible for the absorption.  相似文献   

16.
陈金海  蔡佩佩 《光学学报》1997,17(7):59-865
采用斯塔克调制电旋转激光光谱技术将由偶然简并能级跃迁产生的电旋转信号从非简并能级跃迁中分离出来,因而简化了转动量子态的跃迁谱线,减少了谱线重叠现象,反映了分子能级受偶然简并斯塔克相互作用以及电四极相互作用的特性,非常适合那些转动谱线密集,微扰严重的多原子分子的光谱测量与分析。本文既给出了这种光谱技术的半经典理论模型,又运用微扰理论解释了用该技术所测的NO2分子的转动光谱的形成原因和它们的主要特征。  相似文献   

17.
The output intensity of optically pumped NH3 molecules far-infrared laser (NH3-OPFIRL) was calculated by solving the density matrix equation and by means of iteration method. Meanwhile, the spectral characteristic of AC Stark splitting was studied. Finally, the F-P interferogram of NH3-OPFIRL pumped by CO2-10R(8) line was measured. The experimental results were in good agreement with the theoretical calculation results.  相似文献   

18.
We have performed a series of experiments to observe 11 Stark-induced E1 transitions from the 15650.55 cm-1 level to higher levels with odd parity in samarium (Sm) with optical double-resonance technique. Five Stark-induced E1 transition to the 28233.08, 28613.22, 28913.97, 29041.31 and 29130.03 cm-1 levels have been observed. In order to investigate the contributors to the Stark-induced E1 transition, we have measured scalar and tensor polarizabilities for the observed Stark-induced E1 transitions. Clear Stark splittings were observed for the levels 28233.08 and 28613.22 cm-1, and their tensor polarizabilities were determined for each isotope. Scalar polarizabilities were determined for the 28233.08, 28613.22, 28913.97 and 29130.03 cm-1 levels for the first time. Among them, scalar polarizability for the 28233.08 cm-1 level was the largest in magnitude and was 3.60(10) x 103 kHz/(kV/cm)2 for Sm. We noticed that both scalar and tensor polarizabilities of the 28233.08 cm-1 level depend on the isotope; the difference of magnitude of the scalar and tensor polarizabilities between Sm and Sm were remarkably large and were about 10 and 6 percent, respectively.Received: 10 February 2003, Published online: 30 July 2003PACS: 32.60.+i Zeeman and Stark effects - 32.10.Dk Electric and magnetic moments, polarizabilityD. Angom: Present address: Physical Research Laboratory, Navarangpura, Ahmedabad 380 009, India.  相似文献   

19.
The technique of laser-microwave two-photon spectroscopy has been used to determine the frequencies of a number of transitions in fundamental and hot-bands of the two linear molecules HCCF and FCN. This method has previously only been applied in a systematic way to spectroscopy in NH3 and it was the aim of this investigation to determine to what extent this method was applicable to more normal molecular species. The maximum effective tuning range produced with these molecules was ±3.7 GHz with a microwave power density of ?100 mW/cm2 and a laser power density of ?40 W/cm2. Transition frequencies were determined with accuracies up to ±3 MHz using a Lamb-dip technique. In the case of fluoroacetylene the observation of a number of double resonance signals involving direct l-type doubling transitions allowed determination of l-type doubling constants for the states (v3 = 1, v4 = 1) and (v3 = 1, v5 = 1). The P(12) C18O2 laser line was shown to lie within the Doppler width of the upper l-type doublet R(25) transition of the (ν3 + ν4) ? ν3 hot band. In this particular case velocity-tuned multiple photon dips were observed. The dispersive component of double resonance and two-photon Lamb-dip signals was observed to have opposite phase in two different vibrational states. The possible diagnostic value of this observation is discussed.  相似文献   

20.
The high resolution Stark spectra of the singly deuterated methanol isotope, CH3OD, have been studied using the HCN laser with Stark fields up to approximately 60 000 V/cm. Numerous families of absorption lines have been observed in both parallel and perpendicular polarizations, resulting in the following assignments: with the 311 m line – J K = 181 180 E 2, t = 1; and with the 337 m line – J k = 64 53 E 2, t = 0 and J K = 146 135 A, t = 1. Zero-field frequencies for the assigned transitions are in agreement with Fourier transform measurements and those calculated from the available molecular constants.  相似文献   

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