Fang Wang & Timothy C. Steimle Dept. Chem. & BioChem., Arizona State University, Tempe, AZ,USA The 65 th International Symposium on Molecular Spectroscopy, June 2010 Optical Stark (and Zeeman) Spectroscopy of the B 1 A’’(0,0,0)<-X 1 A’(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: 63 Cu(I=3/2) 69% and 6 5 Cu(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, X 1 A’, properties :  total (D) H.F.Scheafer group (2005)  total 1.363D Predicted Excited State, B 1 A’’, properties :  a (D) ? Exp. Structure (Whitham et al)

B 1 A’’ Controversy concerning nature of excited states Ground state X 1 A’ (1 1 A’) Triplet or Singlet? X 1 A’ (1 1 A’)

 Goals: B. Comparison with isovalent CuF (J, Chem. Phys (2010)) and other Cu containing molecules A. Determination of permanent electric dipole moments of B 1 A’’ and X 1 A’ states for 63 CuOH C. Test for paramagnetism

IV Experimental Set-up Stark plates Optical Stark spectroscopy CH 3 OH & Ar(carrier gas) Well collimated molecular 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 B 1 A’’-X 1 A’(0,0,0-0,0,0) band of CuOH Field-free LIF Spectrum near the origin of K a ’’=0-K a ’=1 sub-band N CuOH Q(N’) CuOH Q(N’) 1 24 N Next slide

1) Observation for field free spectrum-slow scan LIF Signal 95MHz 69MHz 70MHz50MHz 95MHz 67MHz Laser wavenumber cm -1 V The B 1 A’’-X 1 A’(0,0,0-0,0,0) band of CuOH Laser wavenumber cm -1 F B 1 A’’ N=1 X 1 A’ r R(0 00 )-pred. r Q(1 01 )-pred. r P(2 02 )-pred. Is the structure due to the nuclear hyperfine interaction? Quadrupole?, Spin- rotation? Laser wavenumber cm -1 C aa =50MHz

2) Zeeman effect study V The B 1 A’’-X 1 A’(0,0,0-0,0,0) band of CuOH 1150Gauss 0 Gauss LIF Signal 1150Gauss 0 Gauss 1150Gauss 0 Gauss LIF Signal The spectra are only broadened around 20MHz Is the structure due to the nuclear hyperfine interaction? Is the structure due to 1 A/ 3 A mixing? (i.e. spin splitting) 1 A / 3 A mixing interaction

r R(0 00 ) 3) Optical Stark Spectrum of the r R(0 00 ) line &the associated energy level pattern V The B 1 A’’-X 1 A’(0,0,0-0,0,0) band of CuOH N kakc =0 00 N kakc =1 10

r P(2 02 ) 3) Optical Stark Spectrum of the r P(2 02 ) line &the associated energy level pattern V The B 1 A’’-X 1 A’(0,0,0-0,0,0) band of CuOH N kakc =2 02 N kakc =1 10

r Q(1 01 ) a b c * * A B C D E F 3) Optical Stark Spectrum of the r Q(1 01 ) line&the associated energy level pattern V The B 1 A’’-X 1 A’(0,0,0-0,0,0) band of CuOH Stark Induced N kakc =1 10 N kakc =1 11 N kakc =1 01

VI Analysis Symmetric top basis function; CuOH: B 1 A’’<-X 1 A’ Rotational structure Rotational angular momentum operator Rotational Parameters A,B,C N=0 N=1 N=2 ≠0 Matrix representation of the Stark operator  a for the ground state 3.968(32) D Note: levels studied in X 1 A’ 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. 63 CuOH: B 1 A’’<-X 1 A’ 2) Comparison with theory: ground state,  a (exp.)=3.968(32) D  total( D)  a (D) MethodRef CASSCF C.W.Bauschlicher (1986) SDCI(2) Y. Mochizuki(1991) 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. 5D B 1 A’’ Exp. Excited state(B 1 A’’) Is this consistent with Schaefer ?

Molecular orbital diagram for CuOH 10  CuOH(x 1  + ) Linear 77 11 88 99 33 44 11 9a’10a’ 3a’’ 11a’ 4a’’ 12a’ 13a’15a’ 14a’ 5a’’ CuOH(X 1  ’) Bend 5a”  15a’

5a’’(OH3  ) 15a’(4s/3d 0 ) a b Cu O H  (X 1 A’)  (5a”  15a’) aa Small ! 5a”  15a’  (B 1 A”)

CuF X 1    5.26(2 )D 1 r e =1.745A CuO X 2  3/2 4.57(3) D 3 r e =1.724A CuOH X1A’ 3.97(3 )D r e =1.772A CuS X 2  4.31( 15 )D 2 r e =2.051A 3)Compare the dipole moment with CuF 5.26(2) and other Cu containing molecules for the ground state F 3.98 O 3.44 OH 3.03 S 2.58 Electronegativity Molecular beam Laser Induced Fluorescence 1) F. Wang, and Steimle, T. C, THE JOURNAL OF CHEMICAL PHYSICS 132, )T.C. Steimle, W.L. Chang, and D. F. Nachman, J. M. Brown, J.Chem. Phys. 89(12), )X. Zhuang, S. E. Frey and T. C. Steimle (accepted by JCP?) VII Results and Discussions 63 CuOH: B 1 A’’<-X 1 A’

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