自由基分子NH_2υ_2带C0激光磁共振σ谱的观测

采用高灵敏度,高分辨率激光磁共振光谱(LMR)方法在6μm谱段测量了自由基分子NH_2v_2带的σ谱(△M_1=±1)。重复了前人已测过的谱,结果与之较好符合。并观测到了新谱,在14支激光谱线下共获得约115支塞曼(Zeeman)跃迁谱线,其中在6支激光谱线下新测得的谱线91支。     

NO_2的自增宽及N_2O_4和CO_2外加气体压致增宽系数的激光磁共振方法测量

激光磁共振光谱方法被用来研究NO_2的v_3振转带谱线的线宽及压致增宽。通过实验测量及数据分析得到了NO_2的自增宽系数及外来气体N_2O_4和CO_2对它的压致增宽系数,γ_(NO_2-NO_2N_2O_4CO_2)=0.043±0.005,0.014±0.003,0.013±0.003MHz/Pa(HWHM),并由此得到了相应的碰撞截面。这些参数的获得对大气污染监测具有十分重要的意义。     

用可调谐二极管激光光谱仪观测3657—3708cm~(-1)区域CO_2高分辨振转光谱

用可调谐二极管激光光谱仪观测到3657—3708cm~(-1)区域内CO_2各种同位素分子的9个振转谱带。首次观测到~(12)C~(16)O~(17)O的10011—00001谱带和~(12)C~(16)O~(18)O的11111—01101谱带,对其余7个谱带则扩充了其观测振转线的数目。用最小二乘方拟合法计算了各谱带的光谱常数,发现CO_2分子常数表中~(12)C~(16)O~(17)O的10011—00001谱带中心v的计算值比本实验观测值大0.287cm~(-1),而~(12)C~(16)O~(12)O的11111—01101谱带中心v_0的计算值则比本实验观测值小0.048cm~(-1)。     

硅甲烷CARS光谱的研究

测量和分析了硅甲烷(SiH_4)v_1带和v_3带的CARS光谱,并采用偏振CARS技术,解除了v_1带的影响,获得了完全的v_3带的CARS谱.偏振测量和理论模拟计算给出了v_1带和v_3带Q支峰值间的频率位移及两者喇曼跃迁截面平方的比值.     

乙炔(2v_5-v5)、(v_4+v_5)-v_4和(2v_4-v_5)_I-2v_4Q—支高分辨二极管激光光谱

用高分辨二极管激光光谱仪对乙炔v_5区域的几个Q支作了研究.在725cm~(-1)附近观察到(2v_4+v_5)I-2v_4的Q支.并对(2v_5-v_5)和(v_4+v_5)-v_4的Q支进行了观察.观测到一些微扰现象.对观测到的谱线利用最小二乘法进行了拟合,得到了部分分子常数.     

腔外多普勒频率调制激光稳频方法的研究

利用腔外气体吸收池内的SF_6分子饱和吸收线作为参考频率,并通过振动腔外反射镜使进入吸收池的激光的频率受到多普勒调制,实现了对CO_2激光10P(16)和10P(18)支线频率的闭环锁定,最大频率漂移约为7kHz.该法得到的稳频激光输出不仅无寄生频率调制和幅度调制,并且可将激光频率锁定在独立的分子吸收线中心.     

CH_3CN分子ν_1,ν_4,ν_5,ν_7和ν_2+ν_4带的高分辨付里叶变换红外光谱研究

利用分辨率为0.06cm~(-1)的付里叶变换光谱技术研究了CH_3CN分子的v_1,v_4,v_5,v_7和v_2+v_4五个带。观察到了六百多条谱线,并利用最小二乘方方法对这些线进行了拟合,得到了一些新的分子常数。原有的常数也得到了很大的改进。     

SF_6分子V_3带P、R支高分辨吸收光谱

在四个全新频段内记录下SF_6分子吸收光谱,光谱分辨率达多普勒极限;所得108条谱线被分别归属为SF_6v_3振动带的P(29)～P(26)、P(39)～P(36)、R(20)～R(23)、R(334)～R(40).     

高分辨高精密甲胺分子C—N伸缩带的兰姆凹陷饱和吸收红外光谱

甲胺分子(CH3NH2)是最简单的胺类分子,但由于分子中振动-转动-扭动-反转的相互作用使得其能级结构复杂和丰富密集且谱线强度差异很大的波谱,尤其是在频率中心位于1 044cm-1的C—N伸缩振动带。我们使用利用兰姆凹陷光谱技术自主研发的分辨率为0.4 MHz的二氧化碳激光和微波边带红外光谱仪将甲胺分子的C—N伸缩振动带的多普勒光谱中密集重合在一起的上百条谱线逐条分辨开和精密地测量了它们的跃迁频率。将它们标识归类和对J(J+1)作幂级数展开后,我们求得了27个系列的最初跃迁频率和它们的有效转动常数。     

自由基分子NH2ν2带CO激光磁共振π谱的观测

采用高灵敏度、高分辨率激光磁共振光谱(LMR)方法在6μm谱段测量了自由基分子NH₂ν₂带的π谱(ΔM_J=0).测量了前人已测过的谱,结果与之较好符合.并观测到了前人没有观测过的新谱,在3支激光谱线下共获得约13支塞曼(Zeeman)跃迁谱线,其中在2支激光谱线下新测得的谱线10支.利用我们已经测得的^[8]σ谱的新的共振谱线的数值和已取得的激光磁共振谱线的标识方法,可预期得到NH₂的一些新的分子参数.     

Infrared-microwave two-photon spectra of the ν3 bands of 12CH3F and 13CH3F

Infrared-microwave two-photon spectra have been obtained for the ν₃ bands of ¹²CH₃F and ¹³CH₃F with a two-photon spectrometer employing a CO₂ laser and a computer-coupled microwave source operating in the 8–18 GHz region. Even though the intensities of the spectra for the double parity levels in these molecules are inversely proportional to the square of the microwave frequency, transitions have been observed with microwave frequencies of up to 16 GHz. Comparison of these observed two-photon frequencies to frequencies predicted from infrared laser Stark spectroscopy, and to frequencies calculated from vibration-rotation parameters obtained by fitting these and other frequencies, shows agreement to within a few MHz. Spectroscopic parameters for the ground and ν₃ excited states of the two species are reported.     

Pulse Generation by Mode-Beating in a Dual-Wavelength Injection-Locked Laser

Generating of repetition-rate tunable optical pulses is achieved by mode-beating within a CW-operated Fabry-Perot laser. The repetition-rate was tunable from 6GHz to 32GHz and may be synchronized by a low frequency (500MHz) optical input.     

IR absorption measurements and new FIR emission lines in CH3OH by use of a frequency-tunable CW waveguide CO2 laser

The IR absorption in CH₃OH in the vicinity of CO₂ laser lines has been measured quantitatively by use of a 300 MHz tunable waveguide CO₂ laser with output powers of about 3 W. Information on frequency offsets from the CO₂ line centers, small signal and saturated absorption coefficients of FIR laser pump transitions is obtained. Some stronger pump transitions with frequency offsets larger than 50 MHz gave rise to the observation of 8 new FIR emission lines with wavelengths from 43 to 125 μm.     

Conformation of 4-methylcyclohexanone by microwave spectroscopy

The microwave spectrum of 4-methylcyclohexanone has been observed in the frequency region from 18.0 to 26.5 GHz. Both a-type and c-type transitions in the ground state and a-type transitions in four excited states have been assigned. The ground state rotational constants are determined to be A = 4034.39 ± 0.06 MHz, B = 1455.46 ± 0.01 MHz, and C = 1174.06 ± 0.01 MHz. From these data, it is shown that the most stable conformer exists in the chair form with the methyl group in the equatorial position.     

2,3,6-三氟吡啶的转动光谱：氟化对吡啶环结构的影响

本文利用脉冲喷射傅立叶变换微波光谱在2∽20 GHz}的频率范围研究了2,3,6-三氟吡啶基态的转动光谱. 实验转动常数A=3134.4479(2) MHz、B=1346.79372(7) MHz、C=941.99495(6) MHz. 转动跃迁的信号很强使得可以在自然丰度下测定所有单个碳-13和氮-15取代的同位素异构体的转动跃迁. 通过考虑非简谐振动校正,推导出七个同位素异构体的半实验平衡转动常数,利用该半实验平衡转动常数测定了2,3,6-三氟吡啶的准确平衡结构.     

Broadband Brillouin slow light with multiple-longitudinal-mode,tunable pump

We propose and demonstrate broadband Brillouin slow light using a multiple-longitudinal-mode tunable fiber laser as Brillouin pump. A tunable broadband Brillouin pump with a tuning range from 1 520 to 1 555 nm is generated using a fiber ring laser with a semiconductor optical amplifier (SOA) as its gain medium. The pump spectrum consists of a large number of longitudinal modes separated by 6 MHz. The 3-dB bandwidth is about 11.5 GHz, and its fluctuation is less than 100 MHz within the tuning range. An 8-Gb/s data signal can be delayed by up to 83.0 ps (bit error rate < 10 9) at 17-dBm pump power.     

高气压CO2激光器宽带输出频谱特性的理论研究

从理论上研究了高气压CO2激光器的宽带输出频谱特性.结果表明,在20个大气压下,CO2激光器有宽带输出,带宽高达5.0 cm-1(相当于150 GHz),从971 cm-1~976 cm-1,峰值在10R(16)线处,10R(14)线和10R(18)线差不多对称地分布其两侧.很小的增益差异(4.6%)造成了很大的能量输出差异(100多倍).比较了谐振腔内有无色散元件时的输出频谱,理论证明了谐振腔内无任何色散元件时的宽带输出频谱是光滑连续的,而频率依赖的反馈引起了输出频谱很强的精细结构.理论计算结果与实验测量结果符合较好.     

自由基分子NH2υ2带CO激光磁共振σ谱的观测

采用高灵敏度,高分辨率激光磁共振光谱(LMR)方法在6μm谱段测量了自由基分子NH₂υ₂带的σ谱(△M_J=±1)。重复了前人已测过的谱,结果与之较好符合。并观测到了新谱,在14支激光谱线下共获得约115支塞曼(Zeeman)跃迁谱线,其中在6支激光谱线下新测得的谱线91支。     

Saturated absorption spectroscopy in the ultra-violet with a continuous-wave,frequency-doubled,ring dye laser; even isotope shifts on the 6d3D1-6p3P0 transition of HgI

A novel, single-frequency, continuous-wave, ring, dye laser with intra-cavity frequency-doubling has been developed, and used to carry out saturated absorption spectroscopy on the 6s6d³D₁-6s6p³P₀ transition of Hg I at 296.7 nm. Even isotope shifts have been measured by this technique on this transition and are: Hg204-202, 350 ± 10 MHz; Hg202-200, 345 ± 10 MHz; Hg200-198, 310 ± 10 MHz. The shift on transitions from the hyperfine state 6s6d³D₁ ($\text{F =}\text{3}\text{2}$) between Hg199 and Hg201 has also been measured, and is 225 ± 10 MHz.     

The microwave spectrum and dipole moment of heptafulvene

The microwave spectrum of heptafulvene (C₈H₈) has been investigated in the frequency range from 26 to 40 GHz. The following rotational constants have been obtained from a least-squares fit of the measured transition frequencies: A = 3665.972(66)MHz, B = 2004.3165(59)MHz, and C = 1297.5029(90)MHz. From the corresponding moments of inertia it was concluded that heptafulvene has a planar equilibrium structure. The quantitative measurement of the Stark splittings of three transitions have yielded a dipole moment of 0.477(5) D along the a principal axis. A series of satellite transitions accompanied each rotational transition. The satellites have been assigned to the lowest out-of-plane vibration ν₄₂ (B₂) for which a frequency of 70(11) cm^?1 has been determined from relative intensity measurements.