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Application of 2D fluorescence spectroscopy to Metal Containing Species Damian L. Kokkin and Timothy Steimle. Department of Chemistry and Biochemistry

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Why are metal molecules important? Catalysis High temperature chemistry Materials science Astrophysics Outline: 1.Development of 2D spectroscopy for metal containing molecules. 2.Optical Stark Spectroscopy of NiO

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2D fluorescence spectroscopy Applied successfully in the past to study complex chemical environments Two-dimensional fluorescence (excitation/emission) spectroscopy as a probe of complex chemical environmentsBy: Reilly, Neil J.; Schmidt, Timothy W.; Kable, Scott H., JOURNAL OF PHYSICAL CHEMISTRY A, 110, 45, 12355-12359, 2006 Complicated vibronic structure Two dimensional laser induced fluorescence spectroscopy: A powerful technique for elucidating rovibronic structure in electronic transitions of polyatomic molecules, Gascooke, Jason R.; Alexander, Ula N.; Lawrance, Warren D., JOURNAL OF CHEMICAL PHYSICS, 134, 18, 184301, 2011

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The 2Ds in the technique Counts em ex em ex Mol. Beam Laser light

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Why use 2D on metal systems Saves time not having to record an emission (DF) for every band after doing excitation (LIF) and gives a complete snap shot of the systems. Due to the number of electrons in the systems of interest there is a high density of electronic states Facilitates finding polyatomics ( e.g. dioxides, carbenes, hyroxides, etc.)

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Our Experimental Strategy Low Resolution 2D Optimize production Determine excitation wavelengths Determine fluorescence pattern Fluorescent lifetime High Resolution Excitation Measure rotationally resolved spectrum Determine field free constants Measurement Stark and Zeeman effects Magnetic properties Electric dipole moment

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Chamber Nozzle arrangement Mono CCD In house control software Change precursor gas or metal to change chemistry The Experimental Setup 10cm Ablation laser Excitation laser

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Ex #1: Mn + N 2 O MnO X6+X6+ B6+B6+

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Ex. #2: Au + CH 4, CCl 4, OCS Au 2 X1g+X1g+ A0 u +

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Ex #3: Ni + O 2 NiO (narrow scan near 19720 cm -1 )

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Part 2: Application to TMOs The [19.04]O + -X 3 - band of NiO Of the first row transition metal oxides only NiO and MnO have no experimentally determined dipole moments. Rotationally resolved data available for band system in the red, but these bands are highly perturbed. Friedman-Hill and Field, J. Mol. Spec. 155, 259-276,1992 Only relatively low-resolution data is available for other bands in the blue. i.e. unresolved rotational structure observed. Qin et al., Chinese J. Chem. Phys. 26, 5, 512-518, 2013 Balfour et al., Chem. Phys. Lett. 385, 239-243, 2004 Many theoretical prediction of el : C. N. Sakellaris and A. Mavridis, J. Chem. Phys. 138, (2013) 054308 A. Baranowska, M. Siedlecka, and A. J. Sadlej, Theor. Chem. Account (2007) 118, 959 K. P. Jensen, B. O. Ross, and U. Ryde, J. Chem. Phys. 126, (2007) 014103 MethodR e () el (Debye) WFT MRCI-L+DKH21.5984.50.2 WFT (CASPT2)/CCSD(T)1.6264.789 DFT- B3LYP TZVP1.624.78 DFT- BP86 TZVP1.634.11 DFT- PBE0 TZVP1.615.07 DFT- PBE TZVP1.634.08 DFT- BLYP TZVP1.644.02

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Ni+N 2 O NiO (broad scan:18800-19700 cm -1 )

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Ni+N 2 O NiO (Narrow scan near 19608 cm -1 ) Low J lines perturbed.

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X 3 0 - (=0) [19.04] =0 + state Ni+N 2 O NiO RP

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532 nm NiO Ni Rod Stark Plate Filter 53010 nm PMT High Resolution Setup 5%N 2 O in Ar Diode pumped ring laser

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Measure and fit field-free, low J, lines. P(1) P(6) R(0) R(7) Fitting: 1.Hunds case(a) representation for both X 3 0 an [19.04]0 + states 2. X 3 0 parameters fixed to microwave values. B ([19.04] )= 0.42128(3) cm -1 The standard deviation of the fit is 0.0017 cm -1 No Perturbations ! Field-Free, High Resolution, NiO Kei-ichi Namiki and Shuji Saito, Chem. Phys. Lett. 252, 343-347, 1996

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R(0), R(1) and P(1) lines chosen for optical Stark measurements. Field strengths from 1081 to 3243V/cm applied with parallel and perpendicular polarization. 24 Stark shifts were fit using the standard Stark Hamiltonian: H stark =- el. E el (X 3 0 - (=0)) = 4.43 0.04 D, el ([19.04] )= 1.85 0.16 D Optical Stark Measurements

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CoO (2.56 D/)< CuO (2.63 D/) < NiO (2.72 D/) NiO X 3 0 - electronic configuration = 1 4 3 4 8 2 9 2 4 2 CoO X 4 i electronic configuration = 1 3 3 4 8 2 9 2 4 2 Vacancy in the 1 leads to back bonding between the metal and oxygen. CuO X 2 P i has two important electronic configurations = The 10 orbital is the anti-bonding counterpart of the 8 orbital and is back polarized away from the Cu-O bond, thus reducing /R e Comparison to other First Row Transition Metal Oxides MoleculeR e () (D) /R e (D/ ) ScO(X 2 S + )1.66824.550.082.73 0.04 TiO (X 3 D 1 )1.623.340.012.06 0.01 VO(X 4 S - )1.63093.3550.0142.057 0.007 CrO(X 5 P -1 )1.6153.880.132.40 0.08 FeO(X 5 D 4 )1.6194.500.032.78 0.02 CoO (X 4 D 7/2 )1.62784.180.05D2.56 0.03 NiO (X 3 - 0 + )1.62714.430.04 2.720.02 CuO(X 2 P 3/2 )1.72434.570.032.653 0.02 MnO? 1313 8282 9292 3434 4242 Co O 2p 4 4s 2 3d 7 3d 8 NiCu 4s 1 3d 10 8282 1414 1414 8282 9191 10 1 3434 4343 O 2p 4 Cu 4s 1 4p 1 3d 9 Cu O tot (10 ) e - 10 4343

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Application to other systems Metal carbides FeC, FeC 2 and TiC, TiC 2 Gold chemistry Zhang talk (TK09) Silicon Chemistry Si 3 Singlet and triplet fluorescence, and intersystem crossing.

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Acknowledgements NSF DOE