Far-Infrared Laser Assignments for Methylamine

Lees, R. M.; Sun, Zhen‐Dong; Xu, Li‐Hong

doi:10.1007/s10762-007-9309-6

Cited by 6 publications

(2 citation statements)

References 15 publications

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“…19,20 It overlaps well with the CO 2 laser bands and is the source of a number of CH 3 NH 2 far-infrared laser lines optically pumped by CO 2 laser transitions. 38 However, experimental information on this important band is quite limited. Remarkably, the best published spectrum of the C-N stretch fundamental, at a resolution of 1 cm −1 and accuracy of about 0.1 cm −1 , appeared 53 years ago.…”

Section: Introductionmentioning

confidence: 99%

Precision Lamb-dip infrared spectra of the C–N stretching band of CH3NH2 with a CO2-laser/microwave-sideband spectrometer

Sun

Lees

2010

The Journal of Chemical Physics

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We report saturation dip spectroscopy in the C-N stretching band of CH(3)NH(2) with a resolution of 0.4 MHz and an accuracy of 0.1 MHz by use of a CO(2)-laser/microwave-sideband spectrometer. The wide tunability, Lamb-dip resolution, absolute frequency accuracy, and high sensitivity of our dual-mode instrument were all key features in making precise measurements for a range of lines in the densely crowded spectrum with its complex pattern of splittings arising from the large-amplitude CH(3) torsion and NH(2) inversion. We focused on achieving resolution and assignment of transitions within the highly blended Q branch of the C-N stretch and on observations of the important K=0 sequences of Aa and Ea torsion-inversion symmetry. Term values of the latter were fitted to J(J+1) power-series expansions to obtain the K=0 C-N stretching effective B values and substate origins, from which calculated ground-state substate energies were subtracted to yield values of 1044.7061 and 1044.8011 cm(-1) for the Aa and Ea subband origins, respectively. We thereby estimate a mean value of 1044.75(5) cm(-1) for the vibrational band origin and 0.7323(5) cm(-1) for the effective upper-state B value for the C-N stretching fundamental of CH(3)NH(2).

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Section: Introductionmentioning

confidence: 99%

Precision Lamb-dip infrared spectra of the C–N stretching band of CH3NH2 with a CO2-laser/microwave-sideband spectrometer

Sun

Lees

2010

The Journal of Chemical Physics

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“…Thus, each vibration-rotation level of CH 3 NH 2 has Aa, As, Ea and Es sublevels, resulting in a complex vibration-rotation-torsion-inversion energy structures and rich but highly crowded spectra with a wide range of relative line intensities. Therefore, the interesting microwave 1 2 3 4 5 6 7 8 9 10 , far-infrared 11 12 13 14 15 16 17 , and infrared 18 19 20 21 22 23 spectra of CH 3 NH 2 have been extensively studied for many years to explore the splittings and the symmetry species, leading to the valuable application in the detection of interstellar methylamine 24 25 26 27 . In contrast, despite the fact that it is of great practical interest related to optically pumped far-infrared laser lines and interstellar detection, spectroscopic study by the sub-Doppler technique on the stretching of the C−N bond that connects the CH 3 and NH 2 groups has remained rare until recently 28 .…”

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confidence: 99%

Lamb-dip spectroscopy of the C−N stretching band of methylamine by using frequency-tunable microwave sidebands of CO2 laser lines

Sun

Lees

et al. 2016

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Lamb-dip spectroscopy of the C−N stretching band of methylamine has been systematically extended to P-, Q-, and R-branch by using microwave sidebands of a large number of CO2 laser lines as frequency-tunable infrared sources in a sub-Doppler spectrometer. Lamb-dip signals of more than 150 spectral lines have been observed with a resolution of 0.4 MHz and their frequencies have been precisely measured with an accuracy of ±0.1 MHz. More than 30 closed combination loops have been formed, which unambiguously confirm the assignments. For over 150 vibrational excited levels in 27 substates, refined term values have been determined and expanded in J(J + 1) power-series to determine the substate origins and the effective rotational constants. For transitions with Aa torsion-inversion symmetry in torsional state υt = 0, 57 K-doublet lines displaying asymmetry splittings have been observed and the splitting constants for levels with K = 1, 2, and 3 in the excited states have been determined. Our results provide accurate experimental information for spectroscopic studies of the interesting vibrational perturbations and intermode interactions related to the C−N stretching mode, directly support astronomical surveys, and are very relevant in practice to identification and frequency determination of the CO2-laser-pumped far-infrared laser lines of methylamine.

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Large amplitude inversion tunneling motion in ammonia, methylamine, hydrazine, and secondary amines: From structure determination to coordination chemistry

Nguyen

Gulaczyk

Krȩglewski

et al. 2021

Coordination Chemistry Reviews

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Far-Infrared Laser Assignments for Methylamine

Cited by 6 publications

References 15 publications

Precision Lamb-dip infrared spectra of the C–N stretching band of CH3NH2 with a CO2-laser/microwave-sideband spectrometer

Precision Lamb-dip infrared spectra of the C–N stretching band of CH3NH2 with a CO2-laser/microwave-sideband spectrometer

Lamb-dip spectroscopy of the C−N stretching band of methylamine by using frequency-tunable microwave sidebands of CO2 laser lines

Large amplitude inversion tunneling motion in ammonia, methylamine, hydrazine, and secondary amines: From structure determination to coordination chemistry

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