Maykel L. González-Martínez 6 th IMP, Feb. 1-5, 2010. C. Habana.
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Transcript of Maykel L. González-Martínez 6 th IMP, Feb. 1-5, 2010. C. Habana.
Maykel L. González-Martínez
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
OUTLINEOUTLINE
1. MOTIVATION
2. QUASI-CLASSICAL TRAJECTORY METHOD - ANGLE-ACTIONS & CARTESIAN COORDINATES - ECCPST
3. RESULTS - CH2CO CH2 + CO… P(Etrans; jCO) distributions
4. SUMMARY & PERSPECTIVES
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
WHAT, WHY…? WHAT, WHY…? (OBJECT)(OBJECT)
Planetary atmospheres, interstellar media
First-principles amazingly-accurate theoretical predictions
3- to 4-atom systems:3- to 4-atom systems:
Highly detailed experimental results
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
Molecules of biological interest
WHAT, WHY…? WHAT, WHY…? (OBJECT)(OBJECT)
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
Nano-objects
WHAT, WHY…? WHAT, WHY…? (OBJECT)(OBJECT)
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
Clusters
WHAT, WHY…? WHAT, WHY…? (OBJECT)(OBJECT)
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
High interpretative power, intuition…
‘Simplicity’ Extensivity
Prediction (‘smart’ influence)
Uni-, bi-molecular reactions, etc…
WHAT, WHY…? WHAT, WHY…? (METHOD)(METHOD)
Relatively low computational expense
6th IMP, Feb. 1-5, 2010. C. Habana
0 < t < Tmax (R ≤ Rmax)
2.- Hamilton/Newton equations of motion
Ntraj = Ntot
3.- Statistics: From microscopic variables to observables
Quasi-Classical Trajectory Method (QCTM)
t = 01.- (QC) initial conditions
Intro Motivation Theory Results Conclusions 6th IMP, Feb. 1-5, 2010. C. Habana
Unimolecular dissociation of ketene
6th IMP, Feb. 1-5, 2010. C. HabanaIntro Motivation Theory Results Conclusions
6th IMP, Feb. 1-5, 2010. C. HabanaIntro Motivation Theory Results Conclusions
Eb ~ few hundred cm-1
ΔST ≈ 3150 cm-1
(Reproduced from I. -C. Chen, et al J. Chem. Phys. 89, 314 (1988))
RESULTS:
Eexc < Eth(S0) barrier (T1)
Eexc ~ Eth(S0) + 200 cm-1
Pdiss(S0) ~ 80%
↑Eexc: loose tight TS
Effective barrierless polyatomic unimolecular reaction in a single PES
Intro Motivation Theory Results Conclusions 6th IMP, Feb. 1-5, 2010. C. Habana
A. V. Komissarov et al. J. Chem. Phys. 124, 014303 (2006)
RESULTS: ketene… P(ETrans; jCO)
J. Chem. Phys. 126, 041102 (2007)
Intro Motivation Theory Results Conclusions 6th IMP, Feb. 1-5, 2010. C. Habana
A. A. Hoops et al. J. Chem. Phys. 114, 9020 (2001)
Intro Motivation Theory Results Conclusions
J. Chem. Phys. 126, 041102 (2007)
RESULTS: NCO, P(ETrans) ‘explained’…
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
Some problems…Some problems…
QCTM (+ GW): application to polyatomics
6th IMP, Feb. 1-5, 2010. C. Habana
Angle-action variables • Ideal for initial conditions• Not ideal for propagation• Preferable for final statistics
GW requires ~ 10 times more trajectories/vibration… 104!
Microcanonical distribution at the TS
Cartesian coordinates• Not ideal for initial conditions• Ideal for propagation• OK for final statistics
No general transformation from AA to CC!
RESULTS: photo-fragmentation of ketene
J. Chem. Phys. 130, 114103 (2009)
Intro Motivation Theory Results Conclusions 6th IMP, Feb. 1-5, 2010. C. Habana
CH2(x1 - -) <scissor>
CO(x4)
CH2(- - x3) <asym. stretch>
CH2(- x2 -)<sym. stretch>
Intro Motivation Theory Results Conclusions
J. Chem. Phys. 130, 114103 (2009)
6th IMP, Feb. 1-5, 2010. C. Habana
j2 <CO rot.>j1 <CH2 rot.> 1 <j1 proj.>
J <tot. ang. momentum> Jz <J proj.> l <tot. orbital>
Intro Motivation Theory Results Conclusions
J. Chem. Phys. 130, 114103 (2009)
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
Hipothesis: Time-reversed dynamics yields MC ‘distro’ at TS
Hamilton-Brumer…Hamilton-Brumer…
Microcanonical distribution at the products
QCTM: Exit-channel corrected PST
I. Hamilton and P. Brumer, J. Chem. Phys. 82, 595 (1985)
accepted (t’ -t) rejected6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
Some advantages…Some advantages…
QCTM: Exit-channel corrected PST
Initial conditions R | TS flexibly (re-)defined
Threshold behavior
Partitioning into product normal modes
No discretizing + no binning/weighting at t = Tmax
Avoids the strong interaction region
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
Phys. Chem. Chem. Phys. 12, 115 (2010)
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
QCTM: A modification to the PES
Phys. Chem. Chem. Phys. 12, 115 (2010)
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
Phys. Chem. Chem. Phys. 12, 115 (2010)
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
QCTM: How to ‘add’ the rotational resolution?
Phys. Chem. Chem. Phys. 12, 115 (2010)
6th IMP, Feb. 1-5, 2010. C. Habana
ET j = 0j = 2
Least-biased Quantum
ET
ET = E - hw/2 - Bvj(j+1)
Least-biased Quantumwith convolution
Least-biased Classicalwith convolution
or ET = E - ‘exact’ ro-vibrational energy
QCTM: P(ETrans; v) in ABC A + BC(v)h
Intro Motivation Theory Results Conclusions 6th IMP, Feb. 1-5, 2010. C. Habana
Phys. Chem. Chem. Phys. 12, 115 (2010)
Ratio =LB quantum with convolution
LB classical with convolution
ET
1
QCTM
LB quantum with convolution
LB classical with convolutionQCTM Final curve =
Intro Motivation Theory Results Conclusions 6th IMP, Feb. 1-5, 2010. C. Habana
QCTM: P(ETrans; v) in ABC A + BC(v)h
ET
Phys. Chem. Chem. Phys. 12, 115 (2010)
Intro Motivation Theory Results Conclusions
QCTM: How to ‘add’ the rotational resolution?
Phys. Chem. Chem. Phys. 12, 115 (2010)
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
Phys. Chem. Chem. Phys. 12, 115 (2010)
6th IMP, Feb. 1-5, 2010. C. Habana
Intro Motivation Theory Results Conclusions
Phys. Chem. Chem. Phys. 12, 115 (2010)
6th IMP, Feb. 1-5, 2010. C. Habana
• Angle-action variables to Cartesian coordinates for polyatomics
• Problems in S0 PES of CH2CO
• Alternative methodology to apply QCTM to polyatomics: (1) t = 0: angle-actions to Cartesian coordinates; (2) 0 < t < Tmax: ‘association’ perspective (Hamilton & Brumer);
(3) t = Tmax: QC formulae to ‘insert’ rotational resolution.
(1)+(2)+(3) = ¡Ro-vibrational resolution without binning/weighting!
SUMMARY & PERSPECTIVES
Intro Motivation Theory Results Conclusions 6th IMP, Feb. 1-5, 2010. C. Habana
SUMMARY & PERSPECTIVES
• New ab initio PES for CH2CO(S0)
• PESs y aplication to C2H2 C2H + H
• ECCPST to direct processes
• Multi-PES reactions
Intro Motivation Theory Results Conclusions 6th IMP, Feb. 1-5, 2010. C. Habana
Prof. Jesús Rubayo SoneiraInSTEC, C. Habana, CUBA.
Dr. Pascal LarrégarayISM, Bordeaux, FRANCE.
Prof. Jean-Claude RayezISM, Bordeaux, FRANCE.
Dr. Laurent BonnetISM, Bordeaux, FRANCE.
6th IMP, Feb. 1-5, 2010. C. HabanaIntro Motivation Theory Results Conclusions
• Inter-University Agreement on International Joint Doctorate Supervision between the Instituto Superior de Tecnologías y Instituto Superior de Tecnologías y Ciencias AplicadasCiencias Aplicadas (CUBA) and the Université Bordeaux 1Université Bordeaux 1 (FRANCE)
• PNCB/2/04 project of the Departamento de Física GeneralDepartamento de Física General del Instituto Superior de Tecnologías y Ciencias AplicadasInstituto Superior de Tecnologías y Ciencias Aplicadas (CUBA)
MANY THANKS FOR
YOUR ATTENTION
6th IMP, Feb. 1-5, 2010. C. HabanaIntro Motivation Theory Results Conclusions