61 research outputs found
Raman and Infrared Spectra, Conformational Stability, Ab Initio Calculations, and r0 Structural Parameters of Some Organo-Amines and Hydrazines
Polarized Infrared Spectra of Tolane Single Crystal
Polarized infrared spectra of an oriented and very thin tolane
crystal have been measured in the 3500--50 cm-1 region. The symmetry
of the infra red active internal vibrations is proposed on the
basis of the oriented gas model. The application of the vibrational
spectroscopy in studying the conformation of the free tolane molecule
is discussed
Polarized Infrared Spectra of Tolane Single Crystal
Polarized infrared spectra of an oriented and very thin tolane
crystal have been measured in the 3500--50 cm-1 region. The symmetry
of the infra red active internal vibrations is proposed on the
basis of the oriented gas model. The application of the vibrational
spectroscopy in studying the conformation of the free tolane molecule
is discussed
Microwave, infrared and Raman spectra, r0 structural parameters, ab initio calculations and vibrational assignment of 1-fluoro-1-silacyclopentanea)
The microwave spectrum (6500–18 500 MHz) of 1-fluoro-1-silacyclopentane, c-C4H8SiHF has been recorded and 87 transitions for the 28Si, 29Si, 30Si, and 13C isotopomers have been assigned for a single conformer. Infrared spectra (3050-350 cm−1) of the gas and solid and Raman spectrum (3100-40 cm−1) of the liquid have also been recorded. The vibrational data indicate the presence of a single conformer with no symmetry which is consistent with the twist form. Ab initio calculations with a variety of basis sets up to MP2(full)/aug-cc-pVTZ predict the envelope-axial and envelope-equatorial conformers to be saddle points with nearly the same energies but much lower energy than the planar conformer. By utilizing the microwaverotational constants for seven isotopomers (28Si, 29Si, 30Si, and four 13C) combined with the structural parameters predicted from the MP2(full)/6–311+G(d,p) calculations, adjusted r0 structural parameters have been obtained for the twist conformer. The heavy atom distances in Å are: r0(SiC2) = 1.875(3); r0(SiC3) = 1.872(3); r0(C2C4) = 1.549(3); r0(C3C5) = 1.547(3); r0(C4C5) = 1.542(3); r0(SiF) = 1.598(3) and the angles in degrees are: ∠CSiC = 96.7(5); ∠SiC2C4 = 103.6(5); ∠SiC3C5 = 102.9(5); ∠C2C4C5 = 108.4(5); ∠C3C5C4 = 108.1(5); ∠F6Si1C2 = 110.7(5); ∠F6Si1C3 = 111.6(5). The heavy atom ring parameters are compared to the corresponding rs parameters. Normal coordinate calculations with scaled force constants from MP2(full)/6–31G(d) calculations were carried out to predict the fundamental vibrational frequencies, infrared intensities, Raman activities, depolarization values, and infrared band contours. These experimental and theoretical results are compared to the corresponding quantities of some other five-membered rings
Atomic Tunneling from a STM/AFM tip: Dissipative Quantum Effects from Phonons
We study the effects of phonons on the tunneling of an atom between two
surfaces. In contrast to an atom tunneling in the bulk, the phonons couple very
strongly, and qualitatively change the tunneling behavior. This is the first
example of {\it ohmic} coupling from phonons for a two-state system. We propose
an experiment in which an atom tunnels from the tip of an STM, and show how its
behavior would be similar to the Macroscopic Quantum Coherence behavior
predicted for SQUIDS. The ability to tune and calculate many parameters would
lead to detailed tests of the standard theories. (For a general intro to this
work on the on the World-Wide-Web: http://www.lassp.cornell.edu. Click on
``Entertaining Science Done Here'' and ``Quantum Tunneling of Atoms'')Comment: 12 pages, ReVTex3.0, two figures (postscript). This is a
(substantially) revised version of cond-mat/9406043. More info (+ postscript
text) at : http://www.lassp.cornell.edu/ardlouis/publications.htm
Potential energy constants, mean amplitudes of vibration, bastiansen?Morino shrinkage effect, molecular polarizability and absolute raman intensities of the ? g ? -Modes of mercury(I) chloride
Potential energy constants, mean amplitudes of vibration, bastiansen?Morino shrinkage effect and thermodynamic functions in some isotopic species of cyanogen chloride
Mean amplitudes of vibration for an X(YZ)2 molecule with C2v symmetry: Application to B2O3, B2S3 and S(CN)2
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