Fang Wang & Timothy C. Steimle Dept. Chem. & BioChem., Arizona State University, Tempe, AZ,USA

The 65th International Symposium

on Molecular Spectroscopy, June 2010

Optical Stark (and Zeeman) Spectroscopy of the B1A’’(0,0,0)<-X1A’(0,0,0) System of Copper Hydroxide: CuOH

Funded by: NSF

I. Motivation

Copper hydroxide , CuOH, is an ideal molecule because:

a) Nearly filled 3d-orbital

b) Closed shell ground state.

c) Relatively easy to generate

d) Only two isotopes: 63Cu(I=3/2) 69% and 65Cu(I=3/2) 31%

• Bonding in Transition Metal Containing Polyatomic Molecules

Relatively simple electronic state distribution

CuOH is a near prolate symmetric top

a

b

Cu O

H

Previous work -Experimental

Previous work -Theory

No experimental measurement of

Predicted Ground State, X1A’, properties:

total(D)

4.1185.405

5.315

H.F.Scheafer group (2005) total 1.363D

Predicted Excited State, B1A’’, properties:

3.981

a(D)

4.0455.303

5.240

?

Exp. Structure(Whitham et al)

1.77182 0.9616 110.12

B1A’’

Controversy concerning nature of excited states

Ground state

X1A’ (11A’)

Triplet or Singlet?

X1A’ (11A’)

Goals:

B. Comparison with isovalent CuF (J, Chem. Phys. 132 054301 (2010))

and other Cu containing molecules

A. Determination of permanent electric dipole moments

of B1A’’ and X1A’ states for 63CuOH

C. Test for paramagnetism

IV Experimental Set-up

Stark plates

Optical Stark spectroscopy

CH3OH&

Ar(carrier gas)

Well collimatedmolecular beam

Single freq. tunable laser radiation

PMT

Gated photon counter

Metal target (Cu)

Pulse valve

skimmer

Ablation laser

532

Two magnets

Optical Zeeman spectroscopy

0.963”

V The B1A’’-X1A’(0,0,0-0,0,0) band of CuOHField-free LIF Spectrum near the origin of Ka’’=0-Ka’=1 sub-band

N13

65CuOH Q(N’)

24

3

63CuOH Q(N’)

124 N

Next slide

1) Observation for field free spectrum-slow scan

LIF

Sig

nal

95MHz 69MHz

70MHz 50MHz

95MHz67MHz

Laser wavenumber-18400 cm-1

V The B1A’’-X1A’(0,0,0-0,0,0) band of CuOH

Laser wavenumber-18400 cm-1

F2.5

1.50.5

B1A’’N=1

X1A’

rR(000)-pred.

rQ(101)-pred.

rP(202)-pred.

Is the structure due to the nuclear hyperfine interaction? Quadrupole?, Spin-rotation?

Laser wavenumber-18400 cm-1

Caa=50MHz

2) Zeeman effect study

V The B1A’’-X1A’(0,0,0-0,0,0) band of CuOH

1150Gauss

0 Gauss

LIF

Sig

nal

LIF

Sig

nal

1150Gauss

0 Gauss

1150Gauss

0 GaussLIF

Sig

nal

The spectra are only broadenedaround 20MHz

Is the structure due to the nuclear hyperfine interaction?

Is the structure due to 1A/3A mixing? (i.e. spin splitting)1A / 3A mixing

interaction

rR(000)

3) Optical Stark Spectrum of the rR(000) line &the associated energy level pattern

V The B1A’’-X1A’(0,0,0-0,0,0) band of CuOH

Nkakc=000

Nkakc=110

rP(202)

3) Optical Stark Spectrum of the rP(202) line &the associated energy level pattern

V The B1A’’-X1A’(0,0,0-0,0,0) band of CuOH

Nkakc=202

Nkakc=110

rQ(101)

a

bc

*

*

A

B

C

D

EF

3) Optical Stark Spectrum of the rQ(101) line&the associated energy level pattern

V The B1A’’-X1A’(0,0,0-0,0,0) band of CuOH

Stark Induced

Nkakc=110

Nkakc=111

Nkakc=101

VI AnalysisSymmetric top basis function;

Nabasis MKN ,,

CuOH: B1A’’<-X1A’

Rotational structure

Rotational angular momentum operatorRotational Parameters A,B,C

N=0

N=1

N=2

≠0

≠0

Matrix representation of the Stark operator

a for the ground state3.968(32) D

Note: levels studied in X1A’ state are only effected by the “a” component of .

VII Results and Discussions

1) The energy level of excited state is perturbed by the other electronic

states, but the triplet state mixing contribution is small.

63CuOH: B1A’’<-X1A’

2) Comparison with theory: ground state, a (exp.)=3.968(32) D

total(D) a(D) Method Ref.

5.315 5.240 CASSCF C.W.Bauschlicher(1986)

5.405 5.303 SDCI(2) Y. Mochizuki(1991)

4.118 4.045 DK3-CCSD(T)

K. Hirao(2003)

4.118~5.526 K. Hirao(2003)

3.981~5.477 H.E.Schaefer III(2005)

total 1.363~1.843D H.E.Schaefer III(2005)a is less than 0. 5DB1A’’ Exp.

Excited state(B1A’’)

Is this consistent with Schaefer ?

Molecular orbital diagram for CuOH

10

CuOH(x1+) Linear

7

1

8

9

3

4

9a’

10a’

3a’’11a’

4a’’12a’

13a’

15a’

14a’5a’’

CuOH(X1’) Bend

5a”15a’

5a’’(OH3) 15a’(4s/3d0)

a

b

Cu O

H(X1A’)

(5a”15a’)

a

Small !

5a”15a’

(B1A”)

CuF X1 5.26(2 )D1 re=1.745A

CuO X23/2 4.57(3) D3 re=1.724ACuOH X1A’ 3.97(3 )D re=1.772ACuS X2 4.31(15 )D2 re=2.051A

3) Compare the dipole moment with CuF 5.26(2) and other Cu containing molecules for the ground state

F 3.98O 3.44OH 3.03S 2.58

Electronegativity

Molecular beam Laser Induced Fluorescence

1) F. Wang, and Steimle, T. C, THE JOURNAL OF CHEMICAL PHYSICS 132, 054301 20102)T.C. Steimle, W.L. Chang, and D. F. Nachman, J. M. Brown, J.Chem. Phys. 89(12), 19883)X. Zhuang, S. E. Frey and T. C. Steimle (accepted by JCP?)

VII Results and Discussions 63CuOH: B1A’’<-X1A’

3.98

3.58

3.18

2.79

2.39

3.014

2.713

2.411

2.110

1.808

Thank you!