ultrafast processes in molecules
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Ultrafast processes in molecules. X – Case studies of dynamics simulations. Mario Barbatti [email protected]. Case 1: Aminopyrimidine. Aminopyrimidine. Can the Nonadiabatic Photodynamics of Aminopyrimidine Be a Model for the Ultrafast Deactivation of Adenine?. No!. - PowerPoint PPT PresentationTRANSCRIPT
Ultrafast processes in moleculesUltrafast processes in molecules
Mario [email protected]
X – Case studies of dynamics simulations
Case 1: Aminopyrimidine
Aminopyrimidine
• Barbatti and Lischka, J Phys Chem A 111, 2852 (2007)
Can the Nonadiabatic Photodynamics of Aminopyrimidine Be a Model for the Ultrafast Deactivation of Adenine?
No!
Restricted aminopyrimidine
• Barbatti and Lischka, J Phys Chem A 111, 2852 (2007)
Can the Nonadiabatic Photodynamics of Aminopyrimidine Be a Model for the Ultrafast Deactivation of Adenine?
Hum, Maybe !?
1000 amu
Surface hopping: dynamics example
• Nachtigallova, Zeleny, Ruckenbauer, Muller, Barbatti, Hobza, Lischka, JACS 132, 8261 (2010)
Case 2: Azobenzene
Phototrigger
Dynamics
• Pederzoli, Pittner, Barbatti, Lischka, J Phys Chem A 115, 11136 (2011)
Dihedral evolution
Chirality
Biased initial conditions
Initial velocities biased towards positive projection of the clockwise direction
• Pederzoli, Pittner, Barbatti, Lischka, J Phys Chem A 115, 11136 (2011)
Case 3: Cr(CO)6
Cr(CO)6 method assessment
CrCOTheoretical x Experimental deviations in
transition energies and intensities
CC
• Crespo-Otero, Barbatti, J Chem Phys 134, 164305 (2011)
Cr(CO)6 photochemistry
Time constant (fs)
Simulation Experimental
τ1 19 21 ± 1
τ2 41 43 ± 3
τIC 148 68 ± 6
dtet 1 d et t 2 3d et t IC
CrCO
[Cr(CO)6]*
[Cr(CO)5• • •CO]*
[Cr(CO)5]*+CO
Cr(CO)5+CO
0 τ1 τ2 τIC
I II
III
MLCT
MC
Time
Ener
gy
• Kosma, Trushin, Fuss, Schmid, Schneider, PCCP 12, 13197 (2010)• Crespo-Otero, Barbatti, J Chem Phys 134, 164305 (2011)
Case 4: Formamide
Formamide photolysis
• Lundell, Krajewska, Rasanen, J Phys Chem A 102, 6643 (1998)
O
NH2
193 nmGas phase
193 nmAr matrix
193 nmXe matrix
NH3 ••• CO
NH2 + COH
H2 + NCOH
Formamide in Ar matrix
• Eckert-Maksic, Vazdar, Ruckenbauer, Barbatti, Muller, Lischka, PCCP 12, 12719 (2010)
QM: formamide• CASSCF(10,8)/6-31G*
MM: Ar matrix• 661 atoms• 18 K• OPLSAA force field
Dynamics• 100 trajectories• 2 ps• 0.5 fs step
Formamide in Ar matrix
• Eckert-Maksic, Vazdar, Ruckenbauer, Barbatti, Muller, Lischka, PCCP 12, 12719 (2010)
O
NH2
H2
O
NH
0.5 ps O
CH
NH2…. (47%)
0.5 psO
NH2
(22%)
O
NH2
*
(16%)
2 ps
O
CNH3 ..... (15%)
1 ps
+> 2ps
O
CNH3 .....> 2ps
> 2ps?
?
?
Formamide in Ar matrix
• Eckert-Maksic, Vazdar, Ruckenbauer, Barbatti, Muller, Lischka, PCCP 12, 12719 (2010)
Me-formamide in the gas phase
• Crespo-Otero, Mardyukov, Sanchez-Garcia, Barbatti, Sander, ChemPhysChem 14, 827 (2013)
Case 5: Prebiotic reactions
22
Prebiotic route for nucleotides
• Powner, Sutherland, Szostak, JACS 132, 16677 (2010)
• Ferris, Orgel, JACS 88, 1074 (1966)
23
Computational chemistry in action
Dynamics and Chemical Kinetics revealed the
only possible route
QM/MM: hot 4HCN in water
RRKM
24
Photochem in prebiotic synthesis
• Boulanger, Anoop, Nachtigallova, Thiel, MB, ACIE 52, 8000 (2013)
4HCN
purinenucleotides
25
Next lecture:
• Surface hopping with single reference methods
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