Transcript Diapositive 1

DYNAMICS AROUND
CRITICAL FEATURES OF
ENERGY LANDSCAPES
BRUXELLES
LYON
N. Vaeck
M.-C. Bacchus
K. Piechowska
LIEGE
ORSAY
G. Dive
D. Lauvergnat
Y. Justum
B. Lasorne
M. Desouter-Lecomte
I. RESEARCH AREA OF THE TEAM
II. METHODOLOGY
III. CRITICAL REGIONS OF ENERGY LANDSCAPES
IV. OBJECTIVES IN THE RADAM NETWORK
I. RESEARCH AREA
Quantum description of elementary processes in gas phase
1) Electrons: ab initio quantum chemistry calculations of PES
2) Nuclei : wave packet dynamics
Chemical reactivity = exploration of an energy
landscape by a wave packet possibly guided by a laser field
Dynamics
involving few
active degrees
of freedom
Ultrafast
processes
t < 1 ps
Particular regions
leading to
quantum effects
Ultra fast local quantum dynamics
II. METHODOLOGY
Molecular system
H
Segregation between
active (q) and
inactive (Q) coordinates
q : at least the n principal
coordinates involved in the
reaction path
Constrained subsystem
Hconstrained
+ Dissipation
Rigid or flexible
constraints
II. METHODOLOGY
Hconstrained nD
=
VnD(q) + TnD
ab initio
 Select n active coordinates q
Compute a PES VnD(q)
Choose rigid or flexible kinematical model
Qeq(q) = Qc or ∂Qeq(q)/∂q ≠ 0
 Construct the corresponding constrained KEO
TnD
II. METHODOLOGY
Constrained Hamiltonians
ĤnD 
n
n
 f (q)   +  f (q) 
i ,j  1
ij
2
i
i
1
j
i
 v(q)  Veq (q)
i=1
TNUM generates numerically but exactly the values of the
coefficients of the differential operators at any grid point.
D. Lauvergnat & A. Nauts, J. Chem. Phys. 116, 8560 (2002)
D. J. Rush et K. B. Wiberg, J. Phys. Chem. A 101, 3143 (1997),
J. R. Durig et W. Zhao, J. Phys. Chem. 98, 9202 (1994)
S. Sakurai N. Meinander et J. Laane, J. Chem. Phys. 108, 3537 (1998)
M. L. Senent, CPL 296, 299 (1998),
D. Luckhaus, J. Chem. Phys. 113, 1329 2000
III. CRITICAL FEATURES OF ENERGY LANDSCAPES
Non B-O
B-O
A. Regions of
strong non
adiabatic
interaction
B. Bifurcating
regions
Electron transfer
Ultra fast internal
conversion
Conversion of an optical
signal into mechanical
motion
IVR between reaction
coordinate and
deformation
C. Transition states
Rate constant
Tunneling
A. Regions of strong non adiabatic interaction
Conical intersection
Ultra
Fast
decay
Avoided crossing
Up
V2D
funnel
dCO
dCBr or dCCl
M.-C. Bacchus
M.-C. Bacchus
K. Piechowska
N. Vaeck
CASSCF/cc-pvtz
CASSCF/cc-pvdz
Avoided crossing
Diabatic trapping or
up-funnel process
Photoisomerization of the
Yellow proteine
chromophore (p-trans
coumaric acid) in S1 state
up-funnel S1/S2 and turn
around towards another
channel
C. Ko et al. JACS 125, 12710
(2003)
Energie
Energie potentielle
potentielle
Paradoxical decreaseEofE
product yield at
increasing excitation
energy
Coordonnée de réaction
Coordonnée de réaction
R
R
Diabatic trapping
Competitive dissociation of
bromoacetyl chloride
n*(C-Cl)
n*(C-Br)
H
A’’
H
Cl
C
n*(CO)
BrCH2CO+Cl
C
Br
O
Br+CH2COCl
h
A’
l = 248 nm
Experimental
branching ratio
O
Br
C
H2
Cl
Cl:Br = 1.0:0.4
Diabatic trapping
n*(C-Cl)
n*(C-Br)
n*(CO)
BrCH2CO+Cl
Br+CH2COCl
M.D. Person, P.W. Kash & L.J.
Butler, J. Chem. Phys. 97, 355 (1992)
CISD/STO-3G*
h
W.-J. Ding et al, Journal Chemical
Physics 117, 8745 (2002) CAS(8,7)/631G* MRCI
O
Br
C
H2
Cl
B. Lasorne, et al, J. Chem. Phys. 120,
1271, 2004 CASSCF/cc-pvdz (18)
Dynamics of
photodissociation
adiabat 2
2.2
2
CO / 10 -10 m
1.8
1.6
1.4
diabats in orthogonal coordinates
1.2
2.6
1
1.8
2
2.2
2.4
2.6
2.8
CBr / 10-10 m
3
3.2
3.4
3.6
2.4
CO
2
y
q / 10 -10 m
2.2
1.8
adiabat 1
1.6
2.2
Active coordinates
1.4
2
1.2
1.8
1.4
1.6
1.8
2
2.2
2.4
2.6
qx / 10-10 m
m
-10
2.8
3
3.2
3.4
C
O 1.6
/
10
Two 2D subspaces
1.4
Seam
1.2
1
1.8
2
2.2
2.4
2.6 -10
2.8
CBr / 10 m
Spectator modes
3
3.2
3.4
Barrier
3.6
CBr
Two deformations frozen at the
Franck-Condon geometry
adiabat 2
1.9
1.8
1.7
1.6
CO / 10 -10 m
1.5
Other modes optimized in the
first A" excited state
1.4
diabats
1.3
2.2
1.2
2
1.1
1
1.5
2
2.5
CCl / 10-10 m
3
CO / 10 -10 m
1.8
3.5
1.6
1.4
CO
1.2
1
adiabat 1
1.9
1.8
2
2.2
2.4
2.6
2.8
CBr / 10-10 m
3
3.2
3.4
3.6
1.8
M.-C. Bacchus
1.7
1.6
Seam
N. Vaeck
CO / 10 -10 m
1.5
1.4
1.3
1.2
1.1
1
CASSCF/cc-pvdz
1.5
2
2.5
CCl / 10-10 m
3
CCl
3.5
Barrier
Dynamics of photodissociation
CO/CBr subspace
5
0.1
0.15
0.1
5
0.15
0.15
4.5
0.1
0.1
0.1
0.1
1
0.
0.15
0.1
0.1
0.1
5
qy / a.u.
15
0.
4
3.5
0.15
0.15
1
0.
―: t = 0
―: 12 fs
―: 24 fs
―: 36 fs
―: 48 fs
--: 84 fs
--: 96 fs
3
0.15
0.1
0.15
0.10.1
2.5
0.15
0.1
0.15
0.1
0.15
0.15
3
4
5
q / a.u.
6
7
8
x
F-C
CO CBr
Ratio of the
dissociative fluxes in
the CO/CBr and
CO/CCl sides
CO/CBr subspace
5
0.1
5
0.15
1
0.
0.15
4.5
0.1
0.15
15
0.
4
0.1
0.1
0.1
0.1
1
0.
3.5
0.15
0.1
0.1
0.15
3
0.1
0.1
5
qy / a.u.
0.15
0.15
Experimental branching ratio
0.15
0.1
0.1
2.5
0.15
0.1
0.1
0.15
0.15
Cl:Br = 1.0:0.4
0.15
3
4
5
q / a.u.
x
6
7
8
Works in prospect
Cytosine
in collaboration with QCEXVAL
Dynamics in excited states
M. Merchán y L.
Serrano-Andrés, J. Am.
Chem. Soc. 125, 8108
(2003)
University of Valencia, Spain
H. Kang, K.T. Lee ,
S.K. Kim, Chem.
Phys. Letters 359,
Adenine/(H2O)n
213 (2002).
Pump probe experience on
adenine/(H20)n
B. Bifurcating regions : Valley Ridge Inflection Point
Bifurcation of valleys
Bifurcation of ridges
V2D
f
q
H
H
f
C
H
q
O
G. Dive
G. Dive
QCISD 6-31G*
B3LYP 6-31G*
Bifurcating regions
Dynamics of a wave packet around a VRI region
Competition between
Time of spreading in a flat region
Width when entering the VRI region
Curvature of the ridge
V2D
Time of flight along the ridge
Lenght of the ridge
Gradient along the ridge
q
f
Kinetic energy
B. Lasorne, G. Dive, D. Lauvergnat and M.
Desouter-Lecomte,
J. Chem. Phys. 118, 5831 (2003)
Bifurcating regions
P
Dimerisation of
cyclopentadiene
TS2:
TS2 VRI TS1
TS1:
P’
2.895
2.652
1.637
1.963
P
TS2 VRI TS1
P’
P. Caramella, P. Quadrelli & L.
Toma, JACS 124, 1130 (2002)
0 fs
10 fs
20 fs
30 fs
40 fs
50 fs
60 fs
70 fs
0 fs
10 fs
20 fs
30 fs
40 fs
50 fs
60 fs
70 fs
Bifurcating regions
Offers a rich variety of behaviours according to the shape of
the wave packet
Key regions for branching ratios in the unsymmetrical case
Key regions in the control by laser field ?
Key regions in the control by laser field ?
Initial
Wave
packet
150
Target
100
50
0
-50
-100
-150
20
40
60
80
100
120
140
160
180
Target
Wave
packet
Target
x
z
y
After 500 fs
C. Regions around transition states
Rate constant including
tunneling
H transfer
N (E)
N (E)
k (E) 
h  (E)
tunnelin
g
V
N ( E )   N nD ( E -  j )
 (E)
0
Reaction coordinate s
B. Lasorne, F. Gatti, E. Baloïtcha,
H.D. Meyer and M. DesouterLecomte, J. Chem.Phys. 2004 In press
j

by TSWP method
using the flux
operator
eigenvectors
H exchange between hydroxyl
radical and adenine.
N1D ( E )
constrained reaction path
Hamiltonian
Ts  f2 ( s )  s  f1 ( s )  s  v ( s )
2
0.5
0.4
s=s
N1 D ( E )  2 
#
2
2
tr  ( E  Hˆ 1 D ) Fˆ ( E  Hˆ 1 D ) Fˆ
0.3
1
Complex
absorbing
potential
Complex
absorbing
potential
0.2
0.8
N1D(E)
Energy (eV)
1.2
0.1
0.6
tunneling
0.4
0.2
0
-1
-0.5
0
0.5
Reaction coordinate
(ua)coordinate s
Active coordinate
: reaction
G. Dive B3LYP/6-31G**
1
0
0.2
0.3
0.4
0.5
0.6
Energy above reactive complex (eV)
0.7
0.8

Works in prospect
Rate constants
Hydroxyl radical on nucleobases and ribose.
0.5
0
Energie (eV)
E
ev
-0.5
-1
-8
-6
-4
-2
0
2
Coordonnée de réaction
reaction coordinate
4
6
8
C1
OUR OBJECTIVES IN THE RADAM NETWORK
Preliminary step: collect data at microscopic level
Target :
 understand the mechanisms of elementary processes
involving quantum effects after irradiation of biomolecules
 compute and hopefully control branching ratio and rate of
photodissociation
photoisomerization
electron, proton and H transfer
Tools :
Quantum dynamics in reduced dimensionality
in fundamental and excited states
including a laser field
dissipative effects
around conical intersections, avoided crossings and bifurcating
regions
Further step: macroscopic level
Inclusion of these data in kinetic schemes for cellular processes
reaction chains or selforganization
Thank you for your attention