16954-96-4Relevant academic research and scientific papers
Infrared Spectra of Diacetylene-Hydrogen Fluoride Complexes in Solid Argon
Patten, Kenneth O.,Andrews, Lester
, p. 3910 - 3916 (1986)
Diacetylene-hydrogen fluoride complexes and their deuterated counterparts have been characterized in solid argon at 10 K by infrared spectroscopy.The observation of two new sets of H-F stretching, C-H stretching, and C-H bending absorptions indicates that two primary product 1:1 complexes were trapped in the matrix.These absorption bands characterize a C4H2--HF ? complex and a C4H2--FH ? complex whose relative yields exhibit a deuterium substitution dependence consistent with a preference for deuterium in the bonding position.The relative values of the νs (H-F stretching) and ν1 (H-F librational) modes for the diacetylene--HF and acetylene--HF ? complexes reveal weaker hydrogen bonding in the diacetylene--HF complex.Annealing produced comparable increased yields of both 1:1 complexes, suggesting combarable stabilities, and a marked increase in a C4H2--(HF)2 complex.
Emission spectra of alkyl substituted diacetylene radical cations: CH3-CC-CC-R+ with R=H, D, CH3, and CD3; CD3-CC-CC-R+ with R=H, D, CD3; and C2H5-CC-CC-R+ with R=H and C2H5. Competition of the radiative A(?-1) -> X(?-1) and fragmentation decay of their A(?-1) states
Maier, John P.,Marthaler, Oskar,Kloster-Jensen, Else
, p. 701 - 708 (1980)
Optical emission spectra of the radical cations given in the title have been detected in the gaseous phase, using low energy electrons for the excitation.The band systems are assigned to the A(?-1) -> X(?-1) electronic transitions of these cations by reference to the photoelectron spectroscopic data.A vibrational analysis of the emission bands yields the frequencies of some of the totally symmetric fundamentals for the X states and of one or two for the A states that are supplemented by the frequencies inferred from the photoelectron spectra.The title cations excited to their A states exhibit the rare decay behavior in that the radiative relaxation is detected even though fragmentation also takes place.The lifetimes of these cations in the lowest vibrational levels of the A states have been measured.The rates of the radiative and radiationless processes depleting the A states are estimated from these lifetimes and the upper limits of the quantum yields of emission obtained from the cation breakdown curves.Also reported are some other alkyl diacetylene cations for which the radiative pathways could not be detected.
Rate Constants (296-1700 K) for the Reactions C2H + C2H2 -> C4H2 + H and CD2 + C2D2 -> C4D2 + D
Shin, Kuan S.,Michael, J. V.
, p. 5864 - 5869 (1991)
Rate constants for the reactions C2H + C2H2 -> C4H2 + H and C2D + C2D2 -> C4D2 + D have been measured over the temperature range 296-1475 and 1226-1700 K, respectively.For the high-temperature experiments, the method was the laser photolysis-shock tube technique (LP-ST); however, for the room-temperature experiments, the laser photolysis-resonance absorption (LP-RA) technique was used.These techniques utilize the atomic resonance absorption spectroscopy (ARAS) method to monitor H or D atom formation.The results for C2H + C2H2 -> C4H2 + H may be represented by the Arrhenius expression k1H = 3.02*10-10exp(-235 K/T) cm3 molecule-1 s-1 or may be represented by the simple average of all values, k1H = (1.9 +/- 0.8)*10-10 cm3 molecule-1 s-1, over the temperature range 296-1475 K.The rate constant for the reaction C2D + C2D2 -> C4D2 + D can be represented by a simple average of the experimental values, k1D = 1.8 +/- 0.5)*10-10 cm3 molecule-1 s-1, over the temperature range 1226-1700 K.The primary quantum yield for H atom production from acetylene by single-photon absorption at 193.3 nm has also been determined to be 0.21 +/- 0.04.
Accessing long-lived disconnected spin-1/2 eigenstates through spins > 1/2
Claytor, Kevin,Theis, Thomas,Feng, Yesu,Yu, Jin,Gooden, David,Warren, Warren S.
, p. 15118 - 15121 (2014)
Pairs of chemically equivalent (or nearly equivalent) spin-1/2 nuclei have been shown to create disconnected eigenstates that are very long-lived compared with the lifetime of pure magnetization (T1). Here the classes of m
THE HARMONIC FORCE FIELD AND ABSOLUTE INFRARED INTENSITIES OF DIACETYLENE
Koops, TH.,Visser, T.,Smit, W. M. A.
, p. 179 - 196 (1984)
The frequencies, harmonic force field and absolute IR intensities for C4H2 and C4D2 are reported.The experimental harmonized frequencies obey the Teller-Redlich product rule very well.An approximate harmonic force field was obtained from a refinement procedure in which the starting values are adjusted in order to fit the experimental harmonized C4H2 and C4D2 frequencies.The starting force constant values were taken from the harmonic force field of propyne.The integrated IR intensities were determined according to the Wilson-Wells-Penner-Weber method, using nitrogen as a broadening gas at a pressure of 60 atm.The results of the F-sum rule clearly reveal the internal consistency of the measurements.Two sets of values can be derived from the experimental intensities by use of an iterative least-squares fitting procedure.One final set can be selected by applying the isotopic invariance criterion and by comparing with the corresponding derivatives of propyne.The final values are reduced to bond-charge parameters and atomic charges.The bond-charge parameter values are compared with the corresponding values of some common set of intensity parameters recently reported for the series C2H2, CH3CCH and CH3CCCH3.
Formation of D and H Atoms in the Pyrolysis of Benzene-d6 and Chlorobenzene behind Shock Waves
Rao, V. Subba,Skinner, Gordon B.
, p. 5990 - 5995 (2007/10/02)
Dilute mixtures (3-20 ppm) of C6D6 (benzene-d6) were pyrolyzed behind reflected shock waves at temperatures of 1630-1940 K and total pressures of 2-3 atm.Progress of the reaction was followed by analysis for D atoms using resonance absorption spectroscopy.Appearance of D atoms was a first-order process with respect to benzene concentration, and with respect to time during the first part of each experiment.An Arrhenius equation for the formation of D atoms, based on 34 experiments, is kD = 9.7E12 exp(-87100 cal/RT) s-1 with an estimated uncertainty of a factor of 1.5.From measurements of H atoms during pyrolysis of chlorobenzene under similar conditions at 1570-1790 K, the first-order rate constant for the dissociation of chlorobenzene to chlorine atoms and phenyl radicals was found to be k6 = 1.2E14 exp(-90000 cal/RT) s-1, and that for the dissotiation of phenyl radicals to H atoms and other products k3a = 1.2E15 exp(-82000 cal/RT) s-1.With this information, the rate constant for dissociation of benzene-d6 to phenyl-d5 and D atoms was found to be k1D = 4.6E13 exp(-95000 cal/RT) s-1.The rate constant for the exchange reaction H + C6D6 -> C6D5H + D was found to be k4a = 3.2E13 exp(-4200 cal/RT) mol-1 cm3 s-1 over the range 300-1400 K by combining our results with others at lower temperatures.A very simple kinetic model based on a reaction chain with H as carrier can relate our data to other shock-tube work at higher benzene concentrations.
