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Novel photonic materials Manthos G. Papadopoulos Institute of Organic and Pharmaceutical Chemistry. National Hellenic Research Foundation 48 Vas. Constantinou Av. Athens 11635. We will consider a series of derivatives, which have interesting linear and nonlinear optical properties

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Novel photonic materials manthos g papadopoulos

Novel photonic materials

Manthos G. Papadopoulos

Institute of Organic and Pharmaceutical Chemistry.

National Hellenic Research Foundation

48 Vas. Constantinou Av.

Athens 11635


Novel photonic materials manthos g papadopoulos

We will consider a series of derivatives,

which have interesting

linear and nonlinear optical properties

and possible applications

in the photonic industry

  • Unifying features of this work:

  • Molecules with large NLO properties

  • and how these can be interpreted

  • Discovery of mechanisms in order

  • to modify the L&NLO properties


Novel photonic materials manthos g papadopoulos


Novel photonic materials manthos g papadopoulos

Definition of the electric properties

E = E(0) -μαFα - (1/2)ααβFαFβ - (1/6)βαβγFαFβFγ

- (1/24)γαβγδFαFβFγFδ - ...

μα : Dipole moment

ααβ: Polarizability

βαβγ: First hyperpolarizability

γαβγδ:Second hyperpolarizability


Novel photonic materials manthos g papadopoulos

  • Why the L&NLO properties are important:

  • Theory

  • Study of L&NLO processes (e.g. Kerr effect)

  • Intermolecular interactions

  • Applications

  • Design and study of NLO materials

    (optical processing of information,

    optical computing)


Novel photonic materials manthos g papadopoulos

Noble gas derivatives

Definition of the project:

We consider insertion of a noble gas atom, Ng,

in the chemical bond A-B, leading to A-Ng-B.

Specific examples we will consider involve insertion of:

Arin HFleading toHArF

Xe in HCnH leading to HXeCnH

Xe in AuF lading to AuXeF


Novel photonic materials manthos g papadopoulos


Novel photonic materials manthos g papadopoulos

HArF significant?

A. Avramopoulos, H. Reis, J. Li and M. G. Papadopoulos, J. Am. Chem. Soc., 126, 6179 (2004).


Novel photonic materials manthos g papadopoulos

  • Properties of noble gases significant?

  • Synthesis of HArFa (argon fluoro-hydride)

    [first covalent neutral cond. argon der.]

    photolysis of HF in solid argon matrix

    Point of interest:

    The effect of Ar on the NLO

    properties of the resulting derivative

    a. L. Khriachtchev et al., Nature, 406, 874 (2000)


Novel photonic materials manthos g papadopoulos

μ significant?z

αzz

βzzz

Pol

HF

MP2

CCSD(T)

aug-cc-pV5Z

HF

MP2

3.139

2.691

2.578

3.085

2.653

37.61

55.37

59.80

37.80

54.01

-597.8

-1220.9

-1418.1

-578.7

-1102.5

The dipole moment, polarizability and

first hyperpolarizability of HArF (in a.u.)


Novel photonic materials manthos g papadopoulos

μ significant?gg: ground state dipole moment

μee: excited state dipole moment

μge: transition dipole moment

Εge: transition energy

Rationalization ofβzzz

Comparison of

HArF withHF

μgg: 3.473/0.745 a.u.

μee: -0.814/-0.907 a.u.

μge: 1.419/-0.611a.u.

Εge: 0.276/0.570 a.u.

Method: HF/Pol, CIS/Pol

All the above properties contribute so that

βzzz of HArF is much larger than that of HF


Novel photonic materials manthos g papadopoulos

Reliabity of TSM significant?

HArF βzzz=-561.5 a.u. HF/Pol

-340.7 a.u. TSM

HF βzzz=-7.4 a.u. HF/Pol

-5.7 a.u. TSM

  • Reliability of TSM

  • Large effect of Ar


Novel photonic materials manthos g papadopoulos

HF…Ar van der Waals complex significant?

μz=0.983 a.u. (3.473 a.u.)

αzz=19.11 a.u. (34.25 a.u.)

βzzz= -35.09 a.u. (-561.5 a.u.) ratio=16

Charge of Ar: 0.02 (0.56) ratio=28

Method: HF/Pol


Novel photonic materials manthos g papadopoulos

Comparison of significant?HArF with

C6H6

Αzz = 44.74 a.u. (34.25 a.u.)

Method: MP4[SDQ]

P-nitro-aniline

βzzz = 797.5 a.u. ( -561.5 a.u.)

Method: HF/Pol


Novel photonic materials manthos g papadopoulos

The linear and nonlinear optical significant?

properties of derivatives with inserted

Xe


Novel photonic materials manthos g papadopoulos


Novel photonic materials manthos g papadopoulos

H significant?XeF, AuXeF, XeAuF

F. Holka,A. Avramopoulos, O. Loboda, V. Kellö, M. G. Papadopoulos,

Chem. Phys. Letters, 472, 185 (2009)


Novel photonic materials manthos g papadopoulos

HXeF, AuXeF: not synthesized yet

XeAuF: several NgMF have been synthesized

Ng: Ar, Kr, Xe

M: Cu, Ag, Au

X: F, Cl, Br


Novel photonic materials manthos g papadopoulos

Bonding: significant?

Xe - Au bond: covalent [1]

Au - Xe [AuXeF] bond: partially covalent

(AXe)+ F-: significant charge transfer

A= H, Au

The barrier height

AuXeF: 119 kJmol-1

separates

the global minimum (AuF+Xe)

from the local minimum

1. S. A. Cook and M. C. L. Gerry, J. Am Chem. Soc.126, 17000 (2004).


Novel photonic materials manthos g papadopoulos

NBO charges significant?

Method: HF/aug-cc-pVQZ

  • Similar charges on F

  • Quite different charges for Xe of XeAuF and AuXeF


Novel photonic materials manthos g papadopoulos

L&NLO properties significant?

Method: CCSD(T)

Basis set: aug-cc-pVQZ

ECP: Au(60), Xe(28)

The position of Xe has a great effect on αzz and βzzz


Novel photonic materials manthos g papadopoulos

  • β significant?zzz(AuXeF) / βzzz (AuF) = 6.0

  • βzzz(XeAuF) / βzzz (AuF) = 0.7

Method: CCSD(T)

Basis set: aug-cc-pVQZ

  • βzzz(HXeF) / βzzz (HF) = 57.0

Xe may greatly affect βzzz


Novel photonic materials manthos g papadopoulos

Relativistic contribution: significant?

AuXeF

Methods: CCSD(T), Douglas-Kroll

Basis sets: PolX, PolX_DK

βzzz = great effect of relativistic contribution


Novel photonic materials manthos g papadopoulos

Novel compounds derived by significant?

Xe inserted into HC2H and HC4H:

L&NLO properties

A.Avramopoulos, L. Serrano-Andres, J. Li, H. Reis and M. G. Papadopoulos,

J. Chem. Phys., 127, 214 (2007).


Novel photonic materials manthos g papadopoulos

Preparation significant?

HXeC2H and HXeC2XeH:

They are prepared in a low-temperature Xe matrix using UV

photolysis of C2H2 and subsequently annealing at 40-45K

[JACS, 125, 4696 (2003)]

HXeC4H:

Tanskanen et al. reported its preparation

[JACS, 125, 16361 (2003)]

HC2XeC2H:

Ansbacher et al. predicted that the diacetylide Xe exists

as a metastable chemically-bound compound

[PCCP, 8, 4175 (2006)]


Novel photonic materials manthos g papadopoulos

Resonance structures of HXeC significant?2H

Structures Weight (%)a

H–Xe+C–CH (I) 44

H·Xe·CCH (II) 26

H–Xe+–CCH (III) 14

H–Xe2+C–CH (IV) 11

H+XeC–CH (V) 5

Method:CASVB(6,4)/3-21G*


Novel photonic materials manthos g papadopoulos


Novel photonic materials manthos g papadopoulos

NBO Charge Distribution significant?

  • 1 and 2 Xe atoms:

  • Approx. the same charge

  • The chain length does not appear to have an effect


Novel photonic materials manthos g papadopoulos

  • 1 Xe atom significant?

  • End:0.79 e

  • Middle:1.02 e

  • 3 Xe atoms:

  • The middle one has much larger charge

Method:HF/aug-cc-pVZ


Novel photonic materials manthos g papadopoulos

  • Inter-molecular charge transfer significant?

  • {Xe matrix}/HXeC2H

  • Two models

  • 6 Xe atoms octahedrally placed around HXeC2H

  • A1A2=7.56 a.u.

  • A2A3=9.45 a.u.

  • Method:MP2/aug-cc-pVDZ


Novel photonic materials manthos g papadopoulos

(b) 8 Xe atoms arranged in a cube significant?

A1A2=15.12 a.u.


Novel photonic materials manthos g papadopoulos

NBO analysis: significant?

insignificant CT takes place from the Xe environment to HXeC2H:

0.02e in the first model and

0.002e in the second model


Novel photonic materials manthos g papadopoulos

H significant?XeC2H

HC2H

The effect of Xe

Is significant

Method:CCSD(T)/B1


Novel photonic materials manthos g papadopoulos

H significant?XeC2XeH

HXeC2H

The effect of

1 and 2

Xe atoms

Method: MP2/B1


Novel photonic materials manthos g papadopoulos

The effect of Xe significant?

in connection with effect

of the chain length

H2C2H

H2C4H

Δγzzzz = 30 000 au (approx.)

H2XeC2H

H2XeC4H

Δγzzzz = 340 000 au (approx.)


Novel photonic materials manthos g papadopoulos

  • H- significant?Xe-CC-CC-H γzzzz =111 190 a.u

  • H-CC-Xe-CC-H γzzzz =28 488 a.u.

  • H-CC-CC-H γzzzz = 31 224 a.u.

  • Xe leads to a reduction of γzzzz !

  • The position of Xe has a significant effect on γzzzz

  • Method: MP2/aug-cc-pVDZ


Novel photonic materials manthos g papadopoulos

Decomposition channels of HXeC significant?2H

H+ Xe + C2H

HXeC2H

Xe + HC2H

34 kcalmol-1

104 kcalmol-1

The barrier to this exothermic reaction is very high, 64.6 kcalmol-1

and prevents the molecule from dissociation

T. Ansbacher et al., PCCP, 8, 4175 (2006)


Novel photonic materials manthos g papadopoulos

Vibrational properties significant?

Example: HXeC2H

αpvzz = [μ2](0,0)=60.13 a.u

Vibrational Modes:

H-Xe: 1681cm-1 [μ2](0,0)=13.1 a.u

Xe-C: 313 cm-1 [μ2](0,0)=46.8 a.u

The other modes have a negligible contribution (0.23 a.u.)

Method:MP2/aug-cc-pVDZ


Novel photonic materials manthos g papadopoulos

β significant?pvzzz = [μα](0,0) = -835 a.u.

Vibrational Modes:

H-Xe: 1681cm-1 [μα](0,0)=1212 a.u

Xe-C: 313 cm-1 [μα](0,0)=-2079a.u

The other modes have a very small contribution (32 a.u.)

Method:MP2/aug-cc-pVDZ


Novel photonic materials manthos g papadopoulos

  • Local field effect significant?

  • The Xe derivatives have been synthesized in a Xe matrix

  • Thus it would be useful to compute the effect of the Xe environment on the L&NLO properties

  • Example: HXeC2H

  • The discrete local field approximation has been applied

  • Only the dipole and induced dipole interactions between HXeC2H and the Xe environment are considered


Novel photonic materials manthos g papadopoulos

Local field expression: significant?

,

Where

N is the number of molecules in the cell

Vcell is the volume of the cell

ε0is the permitivity of vacuum

α,β,γ are the Cartesian components

Fk’α is the permanent local field effect on molecule k’ due to the surrounding molecules

μk’βis the dipole moment of the free molecule k’

αk’αβis the polarizability of the free moleculek’

L(11) is the Lorentz-factor tensor


Novel photonic materials manthos g papadopoulos

Y significant?

Z

X

Model:

Cubic closed packed with dimensions a=b=c=24.8092 Å

It involves 255 Xe atoms


Novel photonic materials manthos g papadopoulos

Employed data significant?:

HXeC2H: Dipole moment and polarizability of at the CCSD(T) level and

Xe: experimental polarizability value (27.10 au)

Results:

Local field: Fz=-4.4x10-3 au

μz:50.5%

αzz:2.5%

βzzz:20.2%

γzzzz: 12.7%

Changes of properties


Novel photonic materials manthos g papadopoulos

Interpretation of the results significant?

Insertion of Xe in HCnH leads to a large increase of γzzzz

For example:

γzzzz(HXeC2H)=38740 au γzzzz(HC2H)=3380 au

Ratio=11.5

Why?

Method: CASSCF/CASPT2

Basis set:ANO-RCC

Xe:7s6p4d2f1g

C:4s3p2d1f

H:3s2p1d

CASSSF(10,14)


Novel photonic materials manthos g papadopoulos

The computations have shown that insertion of Xe leads to: significant?

(a) Excited states of lower energy

(b) An electronic spectrum which is more dense in low lying states

(c) Many non-zero contributions to the transition dipole moment matrix


Novel photonic materials manthos g papadopoulos

The SOS model significant?

  • The NLO properties are:

  • proportional to products of TDM matrix elements and

  • inversely proportional to products of energy differences

  • Therefore an enhancement to NLO properties is expected


Novel photonic materials manthos g papadopoulos

SOS computed properties significant?

HC2H HXeC2H

αzz = 11.07 au αzz = 26.51 au

γzzzz = 3473au γzzzz = 9102 au

The SOS model reflects the expected trend


Novel photonic materials manthos g papadopoulos

On the electronic structure of significant?H-Ng-Ng-F

(Ng=Ar, Kr, Xe) and the L&NLO properties

of HXe2F

A.Avramopoulos, L. Serrano-Andre, J.Li, M. G. Papadopoulos,

J. Chem. Theory Comput. 6, 3365 (2010).


Novel photonic materials manthos g papadopoulos

Questions significant?:

The diradical character of HNg2F

and the L&NLO properties

Methods:

CASVB, MS-CASPT2, CCSD(T)


Novel photonic materials manthos g papadopoulos

Electronic ground state description significant?

HArArF: 38%σ2 + 56%σσ*

HΚrΚrF: 53%σ2 + 39%σσ*

HΧeXeF: 58%σ2 + 35%σσ*

Increase of the closed shell character:

Xe > Kr > Ar

Method: MS-CASPT2/ANO


Novel photonic materials manthos g papadopoulos

CASVB computations show: significant?

The total weight of the resonance structures

with diradical character is approx.:

99% for HArArF

97% for HKrKrF

87% for HXeXeF


Novel photonic materials manthos g papadopoulos

The singlet-triplet ( significant?3Σ+) gap (STG)

provides an indication for the diradical

character of the system:

STG

HAr2F 4.7 kcal/mol

HKr2F 14.7 kcal/mol

HXe2F 28.7 kcal/mol)


Novel photonic materials manthos g papadopoulos

Wirz suggested that a significant?diradical is a molecule with

STG which does not differ by much more than

≈ 2kcal/mol.

The expression “diradicaloid”

would then extend this range to ≈24 kcal/mol.

So, all the HNg2F are diradicaloids.



Novel photonic materials manthos g papadopoulos

Stability significant?, Electronic Structure

and L&NLO Properties of

HXeOXeF and FXeOXeF

A.Avramopoulos, J. Li, G. Frenking, M. G. Papadopoulos,

J. Phys. Chem. A, 115, 10226 (2011)


Novel photonic materials manthos g papadopoulos

  • HXeOXeF significant? (FXeOXeF) results

    from introduction of 2 Xe atoms

    in HOF (FOF)

  • We have shown that the novel derivatives

    HXeOXeF and FXeOXeF

    can be synthesized, because they are

    protected by high energy barriers



Novel photonic materials manthos g papadopoulos

CASPT2/ANO significant?

CCSD/aug-cc-pVDZ

MP2/aug-cc-pVDZ


Novel photonic materials manthos g papadopoulos

Description of the ground state significant?

HXeXeF 58.0% σ2 + 35% σσ*

HXeΟXeH77.0% σ2 + 9% σσ*

FXeΟXeF76.5% σ2 + 10% σσ*

Insertion of O increases

the closed character


Novel photonic materials manthos g papadopoulos

E significant?1 = 14.9

E2 = 25.5

E3 = 90.3

Units: kcal/mol

Dissociation paths of HXeOXeF calculated at

the CASPT2/ANO level.


Novel photonic materials manthos g papadopoulos

Method: CASPT2/ANO significant?

ZPE has been taken into account

Reactants and products were connected through

Intrinsic Reaction Coordinate (IRC) calculations

E4 = 50.1 kcal/mol

E5 = 31.9 kcal/mol

E6 = 20.1 kcal/mol

HOXeF is another novel derivative


Novel photonic materials manthos g papadopoulos

HXeOXeF is a significant?local minimum and is higher in energy

than several of its dissociation products:

E(HXeOXeF) – E(HOF + 2Xe) = 125.4 kcal/mol

E(HXeOXeF) – E(HO + F + 2Xe) = 85.2 kcal/mol

E(HXeOXeF) – E(OF + H + 2Xe) = 9.0 kcal/mol

HXeOXeF: Metastable


Novel photonic materials manthos g papadopoulos

E significant?1= 49.5 kcal/mol

E2= 40.5 kcal/mol

E3= 32.1 kcal/mol

Dissociation paths of FXeOXeFcalculated at

the CASPT2/ANO level


Novel photonic materials manthos g papadopoulos

E significant?4 = 30.1 kcal/mol

E5 = 13.2 kcal/mol

E6 = 11.1 kcal/mol


Novel photonic materials manthos g papadopoulos

Frenking et al. [1] found that significant?HArArF and HKrKrF

are associated with low-energy barriers.

Thus, they can NOT be observed.

But,

HXeXeF 13.1 kcal/mol

HXeOXeF 14.9 kcal/mol

FXeOXeF 40.5 kcal/mol

Thus O and F increase the barrier

and thus

FArOArF and FKrOKrF

may be observed.

G. Frenking et al., Angew. Chem. Int. Edition,

48, 366 (2009).


Novel photonic materials manthos g papadopoulos

L&NLO Properties significant?

Insertion of O reduces the L&NLO properties

Method: CCD(T)/aug-cc-pVTZ

a. aug-cc-pVDZ


Novel photonic materials manthos g papadopoulos

The L&NLO properties of some significant?

Ni-Dithiolene derivatives

Luis Serrano-Andrés, A. Avramopoulos, J. Li, P. Labéquerie, D. Begué,

V. Kellö, M. G. Papadopoulos, J. Chem Phys., 131, 134312 (2009).


Novel photonic materials manthos g papadopoulos

Points of interest: significant?

  • The low-lying excited states of NiBDT

  • The impressive NLO properties and their interpretation


Novel photonic materials manthos g papadopoulos

State significant?

ΔE/eV

Main configuration

11Ag ( diradicaloid)a

−0.004b

… (π2)2(π3)0 - (π2)0(π3)2

11B1u (pp*)c

0.000b

… (π2)1 (π3)1

.

. 14 states

.

31B3u (σSNi ππ *π *)

3.064

… (σSNi)1 (π 1)1 (π 2)2 (π 3)2

13B1u (diradical)d

0.612

… (π 2)1 (π 3)1

Excited states structure of Ni(S2C2H2)2

a 11Ag [71% (p2)2(p3)0−21% (p2)0(p3)2].

b The energy difference is within the method accuracy. For simplicity the 11Ag state will be considered the ground state at this level.

c 11B1u state 65% [(π 2)1(π 3)1].

d13B1u state 92% [(π 2)1(π 3)1].

Basis set: ANO-RCC

Method: CASSCF/CASPT2


Novel photonic materials manthos g papadopoulos

Remarks: significant?

The main findings of the CASSCF/CASPT2 computations are:

The quasidegenaracy of 11Ag and 11B1u and the large number of low lying excited states.

These features are very likely to lead to large NLO properties


Novel photonic materials manthos g papadopoulos

Table 4. significant?A Basis set study of NiBDTa. The UBHandBHLYP functional was employed. All values are in au.

Property

Basis set

αzz

γzzzzx10-4

6-311G*

222.0

68.1

SDD[Ni]/6-31G*

221.9

55.8

ZPolX

245.3

67.7

aug-cc-pVDZ

244.7

71.9

aug-cc-pVTZ

245.2

68.0

aug-cc-pVQZ

245.4

67.6

Properties of Ni(S2C2H2)2

Method: UBHandHLYP

a The B3LYP/SDD optimized geometry was employed to all calculations.


Novel photonic materials manthos g papadopoulos

Property significant?

Method

αzz

γzzzzx10-4

UBHandHLYP

245.3

67.7

UCCSD

300.5

72.4

UCCSD(T)

364.3

119.0

CASSCF/CASPT2

m/a1b1b2a2b

12/4242 (4s2p,4s*2p*)

67.9/282.2

1647.5/216.0

16/4444 (4s4p,4s*4p*)

243.2/340.7

1102.7/184.7

20/4646 (4s6p,4s*6p*)

309.3/363.8

869.5/153.1

aThe properties were computed numerically. Base field: 0.005 au.

bm: Number of active electrons; a1b1b2a2: Number of orbitals

in subspaces of C2v symmetry.

Basis set: ZPolX


Novel photonic materials manthos g papadopoulos

Method: UBHandHLYP/ significant?

6-31G*


Novel photonic materials manthos g papadopoulos

  • Main points significant?

  • The big second hyperpolarizability of NiBDT

    has been interpreted in terms of the

    quasidegeneracy of the 11Ag and 11B1u states.

    As well as the many low lying excited states.

  • The considered Ni-dithiolene derivatives have

    very big NLO properties.


Novel photonic materials manthos g papadopoulos

The L&NLO properties of [60]fullerene significant?

derivatives

  • Points of interest:

  • Selection of the appropriate method (e.g. functional)

  • Computation of the electronic and vibrational contributions

  • Selection of functional groups

O. Loboda, R. Zalesny, A. Avramopoulos, J. –M. Luis, B. Kirtman, N. Tagmatarchis, H. Reis and M. G. Papadopoulos, J. Phys. Chem. A, 113, 1159 (2009).


Novel photonic materials manthos g papadopoulos

Overshooting significant?

Effect:

3-55 larger


Novel photonic materials manthos g papadopoulos

Ratio: significant?

2

Comment: The substituents were selected according to increasing

Hammett σp constant, which may be used as a measure

of their electron donating capabilities.

Methods: BLYP and HF(it does not have the overshoot problem).


Novel photonic materials manthos g papadopoulos

Ratio: significant?

41

Remark:The ratio of the BLYP and the HF values increases monotonically and becomes

quite large for the strongest donors.


Novel photonic materials manthos g papadopoulos

Concluding remarks significant?

  • Mechanisms which lead to large NLO properties have been discussed

  • Novel derivatives with possible photonic applications have been proposed


Novel photonic materials manthos g papadopoulos

Acknowledgement significant?

Colleagues who contributed to this work:

Dr Aggelos Avramopoulos, NHRF, Greece

Dr Heribert Reis, NHRF, Greece

Dr Luis Serrano Andrés, Universitat de València, Spain

Dr Jiabo Li, SciNet Technologies, USA

Dr Robert Zalesny, NHRF, Greece

Dr Oleksandr Loboda, NHRF, Greece

Professor B. Kirtman, University of California, USA

Dr Josep Maria Luis, University of Girona, Spain

Dr Nikos Tagmatarchis, NHRF, Greece

Professor Vladimir Kellö, Comenius University, Slovakia