STUDY ON THE VIBRATIONAL DYNAMICS OF STUDY ON THE VIBRATIONAL DYNAMICS OF PHENOL AND PHENOL-WATER COMPLEX BY PHENOL AND PHENOL-WATER COMPLEX BY PICOSECOND TIME-RESOLVED IR-UV PUMP-PROBE PICOSECOND TIME-RESOLVED IR-UV PUMP-PROBE SPECTROSCOPYSPECTROSCOPY

Yasunori Miyazaki, Yoshiya Inokuchi, Takayuki EbataYasunori Miyazaki, Yoshiya Inokuchi, Takayuki Ebata

Department of Chemistry, Graduate school of Science,Department of Chemistry, Graduate school of Science,

Hiroshima UniversityHiroshima University

Vibrational Energy Vibrational Energy RelaxationRelaxation

Intramolecular Vibrational energy Redistribution (IVR)

ls>

lb>

ρ ｂ

Vsb)(

2 2EVk bsbIVR

Fermi’s Golden Rule

= anharmonic coupling

= density of bath state

sbV

b

Vibrational Energy Vibrational Energy RelaxationRelaxation

Intramolecular Vibrational energy Redistribution (IVR)

Anharmonic coupling (normal mode analysis)

ls>

lb>

ρ ｂ

Vsb

...6

1

2

1)(

,,

3

,

2

0

jis

jis jisji

is is

qqqqqq

Vqq

qq

VVqV

jis vvv ,,00,0,

ls>

li>

li>lj>

lj>

Csij

Anharmonic term

Csij = qsqiqj = anharmonic constantEvaluation of coupling amongvibrational modes: s, i, j

)(2 2

EVk bsbIVR

Fermi’s Golden Rule

IR spectrum of phenolIR spectrum of phenol%

tran

smitt

ance

in solutionLarge red-shift•Reduced force constant of the OH bondSpectral broadening•Vibrational Energy Relaxation•Fermi Resonance with overtone and/or combination band•Inhomogeneous broadening due to random geometries

etc

Free OH stretchHydrogen-bonded

OH stretchOH

IR spectrum of phenolIR spectrum of phenol

*T. Ebata, et. al., International Journal of Mass Spectrometry, Vol. 159, pp. 111 (1996).

in supersonic molecular beam*

OH

% tr

ansm

ittan

ce

in solution

Free OH stretchHydrogen-bonded

OH stretch

Experimental SetupExperimental Setup

Supersonic Molecular Beam• Directional (minimizing the Doppler effect)

• Population at the lowest vibrational energy level of S0

• Isolated condition

T O F +c hanneltron

mode- loc kedN d: Y A G laser

T H G

1064 nmsample

P G 401S H

P G 401/ D F G

delay- timec ontrol

IR range2300 - 10000 nm

U V range210 - 440 nm

355 nm

Resolution: 14 ps, 5 cm-1

S 0

O H

S 1

IP

IR

UV

UV

doorwaystate

bathstate

U V

U V UV

UVΔ t

τ 1 τ 2

phenol-dphenol-d00

transient 1+1 REMPI*

U V energy

0O H v' - v''

decay

rise

Energy diagram

Y. Yamada, et. al., J. Chem. Phys., Vol. 120, No. 16, pp. 7400 (2004).

a) OH = 32693 cm-1 b) bath = 35461 cm-1

IR

OH

S 0

O H

S 1

IP

IR

UV

UV

doorwaystate

bathstate

U V

U V UV

UVΔ t

τ 1 τ 2

v'

v''

IR wavenumber (cm-1)3620 3660 3700

νOH = 3656 cm-1

150100500- 50

delaytimeΔ t (ps)

phenol-dphenol-d00

Time Profile

a) OH

b) bath state

U V energy

0O H v' - v''

decay

riseIR

OH

Energy diagram

S 0

O H

S 1

IP

IR

UV

UV

doorwaystate

bathstate

U V

U V UV

UVΔ t

τ 1 τ 2

v'

v''

IR wavenumber (cm-1)3620 3660 3700

νOH = 3656 cm-1

decay τ = 14 ps

rise τ = 14 ps

Summary 1Summary 1

S 0

O H

IR

doorwaystate

bathstate

τ １ 14ps

τ ２<<14ps

densityof state

110state/cm-1

ｖ’IVR1 IVR2

S 1ｖ"

*Petkovic, M. Journal of Physical Chemistry A, Vol. 116, pp. 364-371 (2012)

doorway stateγCH

* bath stateνCH

*

IR

OH

OH

phenol-dphenol-d11

Energy diagram transient 1+1 REMPI

a) OD = 33647 cm-1

b) doorway = 34784 cm-1

IR

OD

33500 34000 34500 35000

S 0

O D

S 1

IP

IR

U V

U V

doorwaystate

bathstate

Δ t

U V U V

U V U V

τ 2

IR wavenumber (cm-1)2660 2700 2740

v'

v''νOD = 2700 cm-1

OD106a

U V energy

0O D v' - v''

decay

risedecaydoorwaystate

phenol-dphenol-d11

Time Profile

U V energy

0O D v' - v''

decay

risedecaydoorwaystate

IROD

IR

OD

Energy diagram

S 0

O D

S 1

IP

IR

U V

U V

doorwaystate

bathstate

Δ t

U V U V

U V U V

τ 2

IR wavenumber (cm-1)2660 2700 2740

v'

v''νOD = 2700 cm-1

O D

doorwaystate

- 100 0 100 200 300delay time Δ t (ps)

Time evolution of existence probability after time t

phenol-dphenol-d11

t

mnmmn

n

t

nn

mnn

eEEt

etOD)

11(2

12

2343

1

2222 cos2)(

t

mnmnmmn

n

t

nn

n

mnn

eEEt

etl)

11(2

1

113

121

23

1

2

2222 cos2)(

OD:

Doorway:

Bath: t

nn

n

etbath 2

123

1

1)(

Fitting parameters*

α1 = 0.616 β21 = 0.323

α2 = 0.663 β22 = 0.353

α3 = 0.424 β23 = -0.911

Assignment of the doorway state l2

116a112118b1

Summary 2Summary 2

Energy gapE13 = 0.656 cm-1

E23 = 0.489 cm-1

E12 = 0.167 cm-1

ODl2l1

2700 cm-1

33647 cm-1

1137 cm-1

34784 cm-1

S0

S1

IR

OD

OD

IVR lifetimeτ2

1 = 80 psτ2

2 = 90 psτ2

3 = 60 ps

Y. Yamada, et. al., J. Chem. Phys., Vol. 121, No. 23, pp. 11530 (2004).

Energy diagram

phenol-dphenol-d11▪▪(D(D22O)O)

ODＩＲＯDD

H-bonded νOD = 2600 cm-1

a) OD = 33410 cm-1 b) 34965 cm-1

c) 35211 cm-1

d) 35461 cm-1

U V wavenumber (c m- 1)

33500 34000 34500 35000 35500delay t ime

Δ t (ps )

287

53

20

6.7

transient 1+1 REMPI

S 0

H - bondedO D

S 1

IP

IR

U V

U V

intramolec ularV R

intermolec ularV R

phenol- d1- (D 2O )

phenol- d1 + D 2O

dissoc iation

vibrationalpredissoc iation

U V U V

U V U V

Δ t

τ 1

2560 2600 2640

IR wavenumber (c m- 1)

vO D

τ ２ τ ３

U V energy

0

O D intermolecularintramolecular

Vibrational Predissociation

4003002001000

delay time Δ t (ps)

a)

b)

c )

d)

Time Profile

phenol-dphenol-d11▪▪(D(D22O)O)

ODＩＲＯDD

intramolecularVR τ1 = 12 ps intermolecularVR τ2 = 24 ps

VP τ3 = 100 ps

Energy diagramH-bonded νOD = 2600 cm-1

S 0

H - bondedO D

S 1

IP

IR

U V

U V

intramolec ularV R

intermolec ularV R

phenol- d1- (D 2O )

phenol- d1 + D 2O

dissoc iation

vibrationalpredissoc iation

U V U V

U V U V

Δ t

τ 1

2560 2600 2640

IR wavenumber (c m- 1)

vO D

τ ２ τ ３

U V energy

0

O D intermolecularintramolecular

Vibrational Predissociation

Time Profile

phenol-dphenol-d00▪▪(H(H22O)O)

ODＩＲＯDD

U V energy

0

O H intermolecularintramolecular

Vibrational Predissociation

* Doi, A.; Mikami, N. J. Chem. Phys. Vol. 129, pp. 154308. (2008)

intramolecularVR τ1 = 4 ps * intermolecularVR τ2 = 5 ps

VP τ3 = 25 ps

Energy diagram

S 0

H- bondedO H

S 1

IP

IR

U V

U V

intramolec ularV R

intermolec ularV R

phenol- d0- (H 2O )

phenol- d0 + H 2O

dissoc iation

vibrationalpredissoc iation

U V U V

U V U V

Δ t

3480 3520 3560

vOH

IR wavenumber (cm-1)

τ １ τ ２ τ ３

H-bonded νOH = 3525 cm-1

4003002001000

b)

c )

d)

delaytimeΔ t (ps)

phenol-water complexphenol-water complex

RRKM theory

)(

)(1)( 0

. E

EEW

hEk D

diss

excess energy～600cm-1

excess energy～1525cm-1

HH

DD

3525cm-1

2600cm-1

HH

DD

E0

EDdiss.energy～2000cm-1

Energy scheme

phenol-d1(D2O):

pskRRKM

RRKM 6.431

phenol-d0(H2O):

RRKM

RRKM k

1

1525

Summary 3Summary 3

*Petkovic, M. Journal of Physical Chemistry A, Vol. 116, pp. 364-371 (2012)

dominantIntermolecular vibrationalmode for dissociation*

S 0

O D

IR

S 1

intramolecularvibration

intermolecularvibration

Δ v =0,± 1,± 2,.. Δ v =0

vibrationalpredissociation

Future WorksFuture Works Obtain more data about IVR process of phenol-

derivatives after the OH stretching vibration

Measure the predissociation lifetime of various H-bonded phenol-d1▪(X) complexes

where X = (π-type) acetylene, ethylene, benzene,

(σ-type) dimethyl ether, etc

Effect of intramolecular hydrogen-bonding?Coupling of non-CH related vibrational modes and its IVR rate?

Comparison to the dissociation lifetime of phenol-d0(X) complex