393 research outputs found
An Experimental and Theoretical Investigation of the Skeletal Frequencies of the Paraffin Hydrocarbons and the Far InfraâRed Spectrum of Carbon Tetrachloride
The far infraâred spectra of the paraffin hydrocarbons and of carbon tetrachloride have been investigated. The following bands were located: propane at 370.6 cmâ1, nâbutane at 215 cmâ1, and carbon tetrachloride at 315 cmâ1, the latter showing isotope structure. The contours of the following near infraâred bands for nâbutane were surveyed, and some fine structure was revealed: 1342.9 cmâ1, 1295.6 cmâ1, 1135.6 cmâ1, 956.5 cmâ1, and 740.0 cmâ1. The assignment of the skeletal frequencies of vibration is made, and a theoretical analysis of the skeletal normal frequencies, assuming a valence potential for the molecules propane through pentane, is given.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71089/2/JCPSA6-17-4-393-1.pd
The InfraâRed Absorption Spectrum of Propane
Of the twentyâseven internal degrees of freedom of propane, all nondegenerate, twentyâtwo may appear as fundamental absorption bands. These bands fall into three symmetry classes, designated A1, B1 and B2, and distinguishable by their characteristic contours. Because of overlapping, however, it is impossible in many cases to determine their positions precisely. This is especially true in the regions of the CâH valence and deformation frequencies. Some ten or twelve fundamental bands may be identified with confidence as well as a number of combinations. An A1 band at 870 cmâ1 and a B2 band at 748 cmâ1 have been partially resolved, the line spacing being about 1.47 cmâ1 in agreement with predictions based upon electron diffraction measurements. The fine structure of the B1 bands has not been observed (the predicted spacing is 0.5 cmâ1) but the interval between maxima of the P and R branches is approximately 26 cmâ1 as expected. With 24 cmâatmospheres of gas no bands were observed between 15ÎŒ and 35ÎŒ, although the symmetrical CâC deformation might be expected to produce a band of appreciable intensity within these limits. This frequency has apparently been observed in Raman spectra at 375 cmâ1.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70815/2/JCPSA6-9-7-487-1.pd
Anomalous Rotational Relaxation: A Fractional Fokker-Planck Equation Approach
In this study we obtained analytically relaxation function in terms of
rotational correlation functions based on Brownian motion for complex
disordered systems in a stochastic framework. We found out that rotational
relaxation function has a fractional form for complex disordered systems, which
indicates relaxation has non-exponential character obeys to
Kohlrausch-William-Watts law, following the Mittag-Leffler decay.Comment: Revtex4, 9 pages. Paper was revised. References adde
Stretched exponential relaxation in the mode-coupling theory for the Kardar-Parisi-Zhang equation
We study the mode-coupling theory for the Kardar-Parisi-Zhang equation in the
strong-coupling regime, focusing on the long time properties. By a saddle point
analysis of the mode-coupling equations, we derive exact results for the
correlation function in the long time limit - a limit which is hard to study
using simulations. The correlation function at wavevector k in dimension d is
found to behave asymptotically at time t as C(k,t)\simeq 1/k^{d+4-2z}
(Btk^z)^{\gamma/z} e^{-(Btk^z)^{1/z}}, with \gamma=(d-1)/2, A a determined
constant and B a scale factor.Comment: RevTex, 4 pages, 1 figur
Broadband Dielectric Spectroscopy on Glass-Forming Propylene Carbonate
Dielectric spectroscopy covering more than 18 decades of frequency has been
performed on propylene carbonate in its liquid and supercooled-liquid state.
Using quasi-optic submillimeter and far-infrared spectroscopy the dielectric
response was investigated up to frequencies well into the microscopic regime.
We discuss the alpha-process whose characteristic timescale is observed over 14
decades of frequency and the excess wing showing up at frequencies some three
decades above the peak frequency. Special attention is given to the
high-frequency response of the dielectric loss in the crossover regime between
alpha-peak and boson-peak. Similar to our previous results in other glass
forming materials we find evidence for additional processes in the crossover
regime. However, significant differences concerning the spectral form at high
frequencies are found. We compare our results to the susceptibilities obtained
from light scattering and to the predictions of various models of the glass
transition.Comment: 13 pages, 9 figures, submitted to Phys. Rev.
On-line isotachophoresis. A selective sample pretreatment prior to column liquid chromatographic analysis
Genome-Wide Association Study of Treatment Refractory Schizophrenia in Han Chinese
We report the first genome-wide association study of a joint analysis using 795 Han Chinese individuals with treatment-refractory schizophrenia (TRS) and 806 controls. Three loci showed suggestive significant association with TRS were identified. These loci include: rs10218843 (Pâ=â3.04Ă10â7) and rs11265461 (Pâ=â1.94Ă10â7) are adjacent to signaling lymphocytic activation molecule family member 1 (SLAMF1); rs4699030 (Pâ=â1.94Ă10â6) and rs230529 (Pâ=â1.74Ă10â7) are located in the gene nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NFKB1); and rs13049286 (Pâ=â3.05Ă10â5) and rs3827219 (Pâ=â1.66Ă10â5) fall in receptor-interacting serine/threonine-protein kinase 4 (RIPK4). One isolated single nucleotide polymorphism (SNP), rs739617 (Pâ=â3.87Ă10â5) was also identified to be associated with TRS. The -94delATTG allele (rs28362691) located in the promoter region of NFKB1 was identified by resequencing and was found to associate with TRS (Pâ=â4.85Ă10â6). The promoter assay demonstrated that the -94delATTG allele had a significant lower promoter activity than the -94insATTG allele in the SH-SY5Y cells. This study suggests that rs28362691 in NFKB1 might be involved in the development of TRS
Experimental and theoretical investigation of tunable picosecond pulse generation in longitudinally pumped dye laser generators and amplifiers
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