Application of Sputtering Method to the Observation of Rotational Spectra of Metal-containing Molecules M.Tanimoto, E.Y.Okabayashi, F.Koto, T.Okabayashi Shizuoka University

Introduction Transition Metal Compounds Catalysis Astrophysics New Material Spectroscopic study : difficult High melting point (involatile) Quantum chemical calculation difficult d-electrons high spin multiplicity high orbital angular momentum complicated electronic structure High Resolution Spectroscopy

Formation of transient transition metal compounds 1.Vaporization (High Temperature Cell) Up to 2000 degree C possible High density 2.Discharge of volatile compounds (e.g. Fe(CO) 5 ) Expensive, often toxic Reaction conditions difficult to select 3.Laser ablation Used in combination with FTMW Not suitable for our spectrometer (low concentration) 4.Sputtering reaction Fe + H 2 S FeS

AlCl 3 + He AlCl Experimental Set-up InSb multiplier klystron Amp. PSD Power Supply Heater liq.N 2 pump He PC discharge

High spin state, possibility of metal compound Electrode (stainless steel : Fe, Ni, Cr) Unknown species 6 lines equal intensity rather wide separation CrCl

Sputtering from electrode material  fter observing CrCl FeCl : 6  i 2 lowest spin substate of   = 9/2, 7/2) Linewidth FeCl < CrCl dipole moment FeCl < CrCl Stainless Steel Fe : Cr = 80 : 18

 5/2 Electronic Structure of the NiX radicals

58 Ni 81 Br A 2  5/2 ( ～ 37cm –1 ) J=37.5– (MHz)  –type doubling 120 rotational transitions  -type doubling 58 Ni 79 Br(35 ％ ), 58 Ni 81 Br(34 ％ ) X 2  3/2, A 2  5/2 Assignment Reduced mass ratio anomaly in spectral pattern

ν/J’ ≒ 2B /2J'(MHz) J' X 2  3/2 A 2  5/2 Fortrat Diagram of the NiBr radical large perturbation in X    /2 – simultaneous analysis needed

●● perturbed (obs.) ○○ deperturbed (calc.) ν/J’ ≒ 2B X 2  3/2 A 2  5/2 J’ X 2  3/2 A 2  5/2 B D H q qDqD (60) (60) 1.115(49)1.613(49) -302(32) (47) (10) 10.4(16) MHz kHz  Hz mHz Deperturbed molecular constants ΔG37cm -1 (LIF, fixed)

Summary Features of Sputtering Method various metals various gasses inexpensive, safe to apply wide possibility of compounds Rather low temperature is sufficient Disadvantage low concentration compared with HT-cell high energy state difficult to observe FeCl, CoF, AuO lowest spin state Advantage

mmW studies using the sputtering method

Ar + He + Higher sputtering yield for atoms with more d-electrons Ar + : more effective than He + Sputtering Yield = No. of Sputtered Metal Atoms No. of Rare Gas Ions Sputtering Yield