Calculation of anharmonic effects for the unimolecular dissociation of CH3OOH and its deuterated species CD3OOD using the Rice–Ramsperger–Kassel–Marcus theory

2015 ◽  
Vol 93 (6) ◽  
pp. 655-665
Author(s):  
Qian Li ◽  
Li Yao ◽  
S.H. Lin
Keyword(s):  
Isotope Effect ◽  
Rate Constants ◽  
Anharmonic Oscillator ◽  
Marcus Theory ◽  
Oscillator Model ◽  
Unimolecular Dissociation ◽  
Dissociation Channel ◽  
Anharmonic Effect ◽  
Direct Bond ◽  
Comparison Of Results

Anharmonic and harmonic rate constants for the unimolecular dissociation of CH3OOH and CD3OOD were calculated using the Rice–Ramsperger–Kassel–Marcus (RRKM) theory at the MP2/6-311++G(3df,3pd) level of theory. The anharmonic effect of the reactions was investigated. Comparison of results for the decompositions of CH3OOH and CD3OOD shows that the direct bond dissociation channel, CH3 (D3) O + OH (D), is the most dominant reaction. The anharmonic effect plays an important role in the unimolecular dissociation of both CH3OOH and CD3OOD. For channels CH3 (D3) O + OH (D) and CH3 (D3) + H (D) O2, the anharmonic effect of the unimolecular dissociation of CD3OOD is more pronounced than that of the unimolecular dissociation of CH3OOH. For channel H2 (D2) CO + H2 (D2) O, the anharmonic effect of the unimolecular dissociation of CH3OOH is more pronounced than that of the unimolecular dissociation of CD3OOD. The isotope effect is more distinct in the anharmonic oscillator model.

Anharmonic effect of the unimolecular dissociation of Glycerol to Glycidol

2018 ◽  
Vol 17 (06) ◽  
pp. 1850040
Author(s):  
Qian Li ◽  
Li Yao ◽  
S. H. Lin
Keyword(s):  
Growth Rate ◽  
Comparative Analysis ◽  
High Temperatures ◽  
Rate Constants ◽  
Canonical System ◽  
Dissociation Rate ◽  
Unimolecular Dissociation ◽  
Anharmonic Effect ◽  
Total Energies ◽  
Dissociation Rate Constants

The unimolecular dissociation rate constants of the dehydration of Glycerol to Glycidol were calculated at the MP2/6–311G(d,p) level using the Rice–Ramsperger–Kassel–Marcus (RRKM) theory. The anharmonic effect of the reactions was examined by comparing the rate constants at temperatures (700–3000[Formula: see text]K) of the canonical case and total energies (25654–53089[Formula: see text]cm[Formula: see text]) of the microcanonical system. The calculations showed that high temperatures are required for the reaction to proceed. As the temperatures and total energies increased, the rate of reactions increased. However, the growth rate of the unimolecular dissociation rate constants was high and slower both in the canonical and microcanonical systems. Comparative analysis showed that the anharmonic effect was most significant for the reaction [Formula: see text] and least significant for the reaction [Formula: see text]. The anharmonic effect became more significant as the temperatures and total energies increased. Compared with the microcanonical situation, the anharmonic effect of the canonical system was more pronounced.

VARIATIONAL RANDOM PHASE APPROXIMATION FOR THE ANHARMONIC OSCILLATOR

1991 ◽  
Vol 06 (26) ◽  
pp. 2429-2435 ◽  
Author(s):  
J. DUKELSKY ◽  
P. SCHUCK
Keyword(s):  
Wave Function ◽  
Density Matrix ◽  
Ground State ◽  
Random Phase Approximation ◽  
Anharmonic Oscillator ◽  
Random Phase ◽  
Oscillator Model ◽  
Phase Approximation ◽  
Truncation Scheme

The recently derived Variational Random Phase Approximation is examined using the anharmonoic oscillator model. Special attention is paid to the ground state RPA wave function and the convergence of the proposed truncation scheme to obtain the diagonal density matrix.

scholarly journals A PERTURBATIVE TREATMENT OF A GENERALIZED $\mathcal{PT}$-SYMMETRIC QUARTIC ANHARMONIC OSCILLATOR

2005 ◽  
Vol 20 (39) ◽  
pp. 3013-3023 ◽  
Author(s):  
ABHIJIT BANERJEE
Keyword(s):  
Symmetric Operator ◽  
Anharmonic Oscillator ◽  
Oscillator Model ◽  
Physical Variables ◽  
Perturbative Treatment

We examine a generalized [Formula: see text]-symmetric quartic anharmonic oscillator model to determine the various physical variables perturbatively in powers of a small quantity ε. We make use of the Bender–Dunne operator basis elements and exploit the properties of the totally symmetric operator Tm,n.

Anharmonic Effect of the Unimolecular Dissociation of HFCO and DFCO

2015 ◽  
Vol 62 (7) ◽  
pp. 582-591
Author(s):  
Jingjun Zhong ◽  
Weiwen Wang ◽  
Qian Li ◽  
Wenwen Xia ◽  
Ying Shao ◽  
...  
Keyword(s):  
Unimolecular Dissociation ◽  
Anharmonic Effect

Reactions of trifluoromethyl radicals. V. Hydrogen abstraction from methyl acetate and methyl (2H3)Acetate

1980 ◽  
Vol 33 (7) ◽  
pp. 1437
Author(s):  
NL Arthur ◽  
PJ Newitt
Keyword(s):  
Isotope Effect ◽  
Rate Constants ◽  
Methoxy Group ◽  
Methyl Acetate ◽  
Kinetic Isotope Effect ◽  
Hydrogen Abstraction ◽  
Activation Energies ◽  
Temperature Range ◽  
Kinetic Isotope ◽  
Acetyl Group

Hydrogen abstraction by CF3 radicals from CH3COOCH3 and CD3COOCH3 has been studied in the temperature range 78-242°, and data have been obtained for the reactions: CF3 + CH3COOCH3 → CF3H+[C3H5O2] �������������(3) CF3 + CH3COOCH3 → CF3H+CH2COOCH3������������ (4) CF3 + CD3COOCH3 → CF3D+CD2COOCH3������������ (6) CF3 + CD3COOCH3 → CF3H+CD3COOCH2������������ (7) The corresponding rate constants, based on the value of 1013.36 cm3 mol-1 S-1 for the recombination of CF3 radicals, are given by (k in cm3 mol-1 s-1 and E in J mol-1): logk3 = (11.52�0.05)-(35430�380)/19.145T ���� (3)logk4 = (11.19�0.07)-(34680�550)/19.145T ���� (4)logk6 = (11.34�0.06)-(46490�490)/19.145T ���� (6)logk7 = (11.26�0.05)-(36440�400)/19.145T ���� (7)At 400 K, 59% of abstraction occurs from the acetyl group, and 41 % from the methoxy group. The kinetic isotope effect at 400 K for attack on the acetyl group is 25, due mainly to a difference in activation energies.

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