Far infrared spectrum of CD3OH methanol from 40–220 CM−1

The Fourier transform far-infrared (FTFIR) spectrum of CD₃OH has been obtained from 40–220 cm^?1 at a resolution of 0.002 cm^?1, and partially analyzed. Numerousb-type branches have been assigned in the spectrum, ranging over torsional states fromn=0 to 3. The branches have been fitted toJ(J+1) power-series energy expansions in order to obtainJ-independent branch origins. These in turn have been fitted to the torsion-rotation Hamiltonian, and improved molecular constants have been obtained for the ground vibrational state.     

New FIR Laser Lines from CD3OH

Fourteen new optically pumped far-infrared (FIR) laser lines in the range 46.8 μm to 172.6 μm were discovered in optically pumped CD₃OH. The pump sources include both the CO₂ laser and the N₂O laser. Two theoretically predicted laser lines were observed in this study.     

Laser stark spectroscopy of CD3OH and13CH3OH at 311μm

Laser Stark spectra have been observed for CD₃OH and¹³CH₃OH using the 311 μm line of the HCN laser. The spectra were taken for both parallel and perpendicular polarizations up to 60,000 Volts/cm. For CD₃OH, the two characteristic structures in the spectra have been identified as the J_K=14₄←13₃, A^± doublet in the v_t=0 torsional state. For¹³CH₃OH, the low field structure observed is assigned as J_K=15₃←14₂, A^? in the v_t=0 torsional state.

     

Assignments of optically pumped CD3OH laser lines

Six FIR laser lines from CD₃OH pumped by the 10R(36) and the 10R(18) CO₂ laser lines are assigned to specific rotational energy levels in the excited C?0 stretch state. It is found that their upper laser levels are shifted by a Fermi resonance between the C?0 stretch vibration and the third and forth harmonics of the torsional mode. The Fermi resonance shifts are +0.332 cm^?1 and +2.251 cm^?1 for the upper laser levels pumped by the 10R(36) and the 10R(18) CO₂ laser lines, respectively. Calculated frequencies of the pump and the laser transitions agree with those of the pump CO₂ laser lines and the observed FIR laser lines within estimated accuracy.     

Measurement of Laser Frequencies from CD3OH and CD3OD up to 8.6 THz

Twenty two laser frequencies, whose values range from 1.6 to 8.6 THz, have been measured for the first time using heterodyne techniques. These laser emissions were generated by an optically pumped molecular laser that used either CD₃OH or CD₃OD as its lasing medium. At least three of the observed laser emissions generated by CD₃OH were discovered during this investigation and the first laser frequencies measured for CD₃OH above 8 THz are reported. The laser frequencies were measured with fractional uncertainties up to ± 2 × 10^?7, of sufficient accuracy to confirm two proposed far-infrared laser assignments. The offset frequency of the CO₂ pump laser with respect to its center frequency was also measured for nearly all laser emissions generated by CD₃OH.     

13CD3OH and12CD3OH optically pumped by a13CO2 laser: Observations and assignments of FIR laser lines

In this work we report the first observation of FIR laser lines from¹³CD₃OH pumped by the¹³CO₂ isotope laser. Using the same pump we have also found 3 new lines from¹²CD₃OH. Tentative assignments for the absorption and emission transitions of the observed lines are also proposed.     

New optically pumped FIR laser lines in CD3OH

In this work we report laser action in 69 new FIR laser lines in CD₃OH optically pumped by a regular cw CO₂ laser. We have performed measurements of laser wavelength, optimum pressure of the gas, relative polarization and intensity on all lines, including some previously known.     

Electric field effects on roto-vibrational transitions of13CD3OH1

We used a Stark-Optoacoustic cell and hybrid waveguide resonators to perform an Infrared and Far Infrared Stark Spectroscopy study on some transitions of¹³CD₃OH. Different behaviours of the transitions in the presence of a d.c. electric field were observed. The Stark splittings of six FIR laser lines ranging from 34 to 136 MHz/kVcm^?1 were determined. The analysis of the behaviour of the IR and FIR transitions in the presence of the external electric fields gives important and exclusive information on the levels involved in the transitions.     

13CH3OH and13CD3OH optically pumped fir laser: New large offset emission and optoacoustic spectroscopy

27 new, large offset, FIR laser lines from¹³CH₃OH and one from¹³CD₃OH have been discovered by pumping with a high tunability waveguide CW CO₂ laser. Optoacoustic measurements of isotopic methyl alcohol have also been performed and the pump offsets of the new and of previously known lines have been measured and checked. Frequency tunability by Stark effect has been observed for 6 strong lines. Some assignments are discussed.     

Measurements and assignments of new large offset CD3OH FIR laser lines

By using an acoustooptic modulator we extend the 300 MHz tunability of a waveguide CO₂ laser to 480 MHz. The CD₃OH was optically pumped by the 10R(32), 10R(34), and 10R(36) CO₂ laser lines, and 17 new FIR laser lines were discovered. The Stark effect on previously known FIR laser lines was investigated, and some tentative FIR laser lines assignments are suggested.     

New fir laser lines and frequency measurements from optically pumped13CD3OH3

We report the discovery of 57 new fir laser lines from¹³CD₃OH molecule optically pumped by a waveguide CO₂ laser of 300 MHz tunability. For all lines, precise frequency offset measurements between the CO₂ line center and the center of the absorbing¹³CD₃OH line were performed using the transferred Lamb-Dip technique. We have also measured directly the frequency of seven FIR laser lines by heterodyning with already known laser lines. We present a complete list of all known laser lines (134) and frequency measurements (24) for this molecule.     

New FIR laser lines and frequency measurements for optically pumped CD3OH

Twenty new cw FIR laser lines in CD₃OH, optically pumped by a CO₂ laser, are reported. The frequencies of 39 of the stronger laser lines were measured relative to stabilized CO₂ lasers with a fractional uncertainty, as determined by the reproducibility of the FIR frequency itself, of 2 parts in 10⁷.     

Experimental investigation of13CD3OH infrared transitions by means of optoacoustic spectroscopy

A systematic investigation of¹³CD₃OH infrared transitions around CO₂ laser line emissions is performed by means of optoacoustic detection. Using a waveguide CO₂ laser of 290 MHz tunability and, in some cases, an acoustooptic modulator to provide an extension of 180 MHz, 108 transitions are observed. Measurements of pump off-set and relative intensity have been performed. The data may be compared with those previously reported of high resolution Fourier Transform spectroscopy.     

Torsional refilling transitions in tea-pumped CH3OH fir lasers with associated high-resolution fir spectra

It is proposed that a number of the high-frequency far-infrared (FIR) laser lines observed when CH₃OH is optically pumped by high-power CO₂ TEA lasers can be identified as refilling torsional transitions within the vibrational ground state. Assignments are presented for 8 such TEA-pump/FIR-laser refilling systems. To provide support for the assigned laser frequencies, high-resolution Fourier transform FIR spectra of CH₃OH have been obtained and partially analyzed in the torsional transition region.     

乙醇/水混合团簇的多光子电离质谱研究

利用激光器(输出波长355nm)激发乙醇和水二元混合团簇中的离子-分子反应,运用飞行时间质谱技术检测反应后生成的团簇离子.实验观测到多个序列的质子化团簇离子:(C2H5OH)nH 和(C2H5OH)n(H2O)mH (n=1-12,m=1-4),其产生是通过团簇内的质子转移反应.通过对团簇离子的峰强度同乙醇数目n和水分子数目m的关系的研究发现,团簇离子(C2H5OH)8(H2O)H 是幻数结构.     

Fourier Transform Spectrum and Term Values for the CO-Stretching Mode of CD3OH Methanol

The Fourier transform infrared (FTIR) spectrum of the CO-stretching fundamental band of CD₃OH has been recorded at a resolution of 0.002 cm^-1. Assignments are reported for 35 subbands in the n = 0 ground torsional state, covering K = 0 to 9 for all torsional symmetries plus K = 10 A, and 12 assorted A and E subbands in the n = 1 first excited torsional state ranging from K = 0 up to K = 5. The subband wavenumbers have been fitted to J(J + 1) power-series energy expansions to obtain subband origins and a compact representation of the spectral observations. With the use of known ground-state energies, CO-stretch energy term values have been determined and tabulated. Least-squares fitting of the subband origins to a fourth-order Hamiltonian model for the CO-stretch mode is discussed.     

Identification of the high efficiency 127μm FIR laser line of13CD3OH

An assignment is proposed for the strong 127.0 μm far-infrared (FIR) line of¹³CD₃OH known to be pumped with very high efficiency by the 10P(8) CO₂ laser line. On the basis of spectroscopic clues derived from calculated molecular parameters and energies for¹³CD₃OH, the 127 μm line is identified as the (nτK,J)=(116,17)→(125, 16) transition, and its companion 462.8 μm line as the (116,17)→(116,16) transition. Proposed partial assignments and predictions are also discussed for a number of other FIR laser lines in¹³CD₃OH, CD₃OH, CD₃OD, CH₃OD, CH₃OH and¹³CH₃OH.     

Far-infrared laser stark spectroscopy of CH3OH and13CH3OH

The high resolution laser Stark spectra of methanol and¹³C-substituted methanol have been studied up to Stark fields of about 60 000V/cm with the HCN and DCN lasers. Numerous families of absorption lines have been observed in both parallel and perpendicular polarizations. For methanol, the transitions J _k =7₅ ← 6₄ A,υ _t=0; J _k =11₄ ← 10₃ E _l ,υ _t=0; and J _k =17₃ ← 16₂ E₂,υ _t=0 have been identified while the assignments for¹³C-substituted methanol are J _k =14₈ ← 15₇ A,υ _t=0; J _k =15₃ ← 14₂ A⁺,υ _t=0; J _k =10₇ ← 9₆ A,υ _t=0; and J _k =27₉ ← 27₈ E₁,υ _t=0. Zero-field frequencies for the assigned transitions are given with improved accuracy over those calculated from available molecular constants, especially for¹³CH₃OH.