Millimeter- and submillimeter-wave length spectrum of the partially deuterated ammonias; A study of inversion, centrifugal distortion, and rotation-inversion interactions

141 internal rotation doublets (282 transitions, among which 174 new measurements) of acetaldehyde in its ground torsional state have been measured up to 600 GHz (J ≦ 32). An overall fit of the measurements (including the lines identified by previous workers) using the Internal Axis Method has allowed us to accurately determine the rotational, centrifugal distortion and internal rotation constants. The quality of the fit is good enough to permit the accurate prediction of transition frequencies of possible astrophysical interest.

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CP's Triple-bond Strength Experienced in its THz Spectrum

Zeitschrift für Naturforschung A ◽

10.1515/zna-1999-3-405 ◽

1999 ◽

Vol 54 (3-4) ◽

pp. 187-190 ◽

Cited By ~ 2

Author(s):

H. Klein ◽

E. Klisch ◽

G. Winnewisser ◽

A. Königshofen ◽

J. Hahn

Keyword(s):

Liquid Nitrogen Temperature ◽

Submillimeter Wave ◽

Frequency Region ◽

Rotational Spectrum ◽

Red Phosphorus ◽

Centrifugal Distortion ◽

Temperature Analysis ◽

Molecular Constants ◽

Quantum Numbers ◽

Vibrational Ground State

The submillimeter-wave rotational spectrum of the CP radical in the electronic and vibrational ground state (X2Σ+) was recorded in the frequency region between 572 GHz and 1.05 THz, covering rotational quantum numbers from N = 11 up to 21. The CP radical has been produced by discharging CH4 over red phosphorus buffered with Ar at liquid nitrogen temperature. Analysis of the new rotational data of CP together with those available in the literature allows the derivation of an accurate set of molecular constants, including rotational, B0 = 23859.91521(28) MHz and the centrifugal distortion constant D0 = 39.8140(19) kHz, the fine structure and hyperfine structure parameters. The stiffness of the CP bond can be inferred by requiring only one distortion constant D0 to fit the measured rotational spectrum.

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Millimeter and submillimeter wave rotational spectrum and centrifugal distortion effects of D2S

Journal of Molecular Spectroscopy ◽

10.1016/0022-2852(72)90127-0 ◽

1972 ◽

Vol 41 (1) ◽

pp. 123-136 ◽

Cited By ~ 54

Author(s):

Robert L. Cook ◽

Frank C. De Lucia ◽

Paul Helminger

Keyword(s):

Submillimeter Wave ◽

Rotational Spectrum ◽

Centrifugal Distortion

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The Millimeter and Submillimeter-Wave Spectrum of Dimethylether

Zeitschrift für Naturforschung A ◽

10.1515/zna-1990-0518 ◽

1990 ◽

Vol 45 (5) ◽

pp. 702-706 ◽

Cited By ~ 21

Author(s):

W. Neustock ◽

A. Guarnieri ◽

J. Demaison ◽

G. Wlodarczak

Keyword(s):

Internal Rotation ◽

Wave Spectrum ◽

Submillimeter Wave ◽

Rotational Spectrum ◽

Centrifugal Distortion ◽

Centrifugal Distortion Constants

Abstract We report the analysis of the rotational spectrum of dimethylether measured between 60 and 400 GHz. Rotational and quartic centrifugal distortion constants are given. Internal rotation splittings are analysed with the I AM method. The value of is compared to the values obtained for similar molecules

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Probe size and 5th-order aberration

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100125609 ◽

1987 ◽

Vol 45 ◽

pp. 134-135 ◽

Cited By ~ 1

Author(s):

Zhifeng Shao

Keyword(s):

Electron Probe ◽

Spherical Aberration ◽

Wave Length ◽

Cylindrical Symmetry ◽

Electron Wave ◽

Third Order ◽

The Third ◽

Probe Radius ◽

Small Probe ◽

Probe Size

A small electron probe has many applications in many fields and in the case of the STEM, the probe size essentially determines the ultimate resolution. However, there are many difficulties in obtaining a very small probe.Spherical aberration is one of them and all existing probe forming systems have non-zero spherical aberration. The ultimate probe radius is given byδ = 0.43Csl/4ƛ3/4where ƛ is the electron wave length and it is apparent that δ decreases only slowly with decreasing Cs. Scherzer pointed out that the third order aberration coefficient always has the same sign regardless of the field distribution, provided only that the fields have cylindrical symmetry, are independent of time and no space charge is present. To overcome this problem, he proposed a corrector consisting of octupoles and quadrupoles.

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New Feasible Concepts of Aberration Correction for Realizing High-Resolution Electron Microscopes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100179762 ◽

1990 ◽

Vol 48 (1) ◽

pp. 202-203

Author(s):

H. Rose

Keyword(s):

Spherical Aberration ◽

Wave Length ◽

Electron Wave ◽

Optical Lens ◽

Resolution Electron ◽

Rotationally Symmetric ◽

Electron Microscopes ◽

The Cost ◽

Imaging Performance ◽

Acceleration Voltage

The imaging performance of the light optical lens systems has reached such a degree of perfection that nowadays numerical apertures of about 1 can be utilized. Compared to this state of development the objective lenses of electron microscopes are rather poor allowing at most usable apertures somewhat smaller than 10-2 . This severe shortcoming is due to the unavoidable axial chromatic and spherical aberration of rotationally symmetric electron lenses employed so far in all electron microscopes.The resolution of such electron microscopes can only be improved by increasing the accelerating voltage which shortens the electron wave length. Unfortunately, this procedure is rather ineffective because the achievable gain in resolution is only proportional to λ1/4 for a fixed magnetic field strength determined by the magnetic saturation of the pole pieces. Moreover, increasing the acceleration voltage results in deleterious knock-on processes and in extreme difficulties to stabilize the high voltage. Last not least the cost increase exponentially with voltage.

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