1 N. NISHIMIYA and T. YUKIYA Tokyo Polytechnic University, Kanagawa, JAPAN. HIGH – RESOLUTION LASER SPECTROSCOPY OF THE A 3 Π 1 ← X 1 Σ + SYSTEM OF ICl IN 0.8  m REGION

2 Our Research Laser spectroscopy of electronic band system of halide molecules. Target: ICl, IBr, I2, and Br2 For establishing the frequency standard in the near infrared region. In this time we have measured the A-X spectra of ICl in the region of cm -1 region.  ICl spectrum is weak comparing to other halogen molecules.  It is easy to assign, because of its wide spectrum intervals.  One spectrum at least can be found within a continuous tuning range of a titanium sapphire laser in the 0.8  m region. The constants have determined by taking into consideration isotopic reduced mass ratio.

3 References (1)J.A.Coxon,et. al.,``The A 3  1u  X 1  + Absorption Spectrum of ICl. '', J.Mol.Spectrosc.79, 363 (1980) (2)J.A.Coxon and M.A.Wickramaaratchi,``The A 3  1  X 1  + Emission Spectrum of ICl in the Near Infrared. '', J.Mol.Spectrosc.79, 380 (1980) (3)J.C.DBrand and A.R.Hoy,``High Vibrational Level of the the X state of ICl, and the Electronic-Coriolis Coupling of the X and A states.'',J.Mol.Spectroscopy, 114, 197 (1985) (4)J.C.D.Brand, et.al. ``The A’( 3  2 ) of ICl”, J.Mol.Spectrosc., 113, 388 (1985) (5)H.G.Hedderich, et.al.,``The High-Resolution Infrared Spectrum of Iodine Monochloride.'', J.Mol.Spectrosc., 155, 384 (1992). (6)C.M.Western, ``Variation of the electronic wave function with internuclear separation: High- resolution spectroscopy of the A 3  state of I35Cl near the dissociation limit.’’, J.Chem.Phys., 98, 1826 (1993) (7)T.J.Slotterback, et.al.,``Hyperfine measurements in the X and B electronic states of I35,37Cl: Probing the ionic character of the chemical bond.'', J.Chem.Phys., 101, 7221(1994) (8)T.J.Slotterback, et.al.,``Hyperfine analysis of the mixed A 3  1 v=28 and X 1  + v=69 states of I35Cl”, J.Chem.Phys., 103, 9125(1994)

4 J+1(odd)  + f-level e-level  J=0 Q  Type doubling   J=-1 P   J=1 R J(even) Energy Internuclear distance r  J+1(odd) J(even)   - e-level f-level  -  +  - Potential Energy P and R line shape

5 15Hz 400 MHz Frequency Modulation: Saturated Vapor at Room Temp. Cell Temperature and Gas Pressure: 14.4m Optical Path Length: Conditions Lock in Amp. Wave Meter Opt. Fiber Generator Function PC BusLocal M M BS Lock in Amp. M Ti:Al 2 O 3 Laser Controller Laser Sweep signal Etalon Driven Signal BRF Driven Signal D/A Servo Amp. Ar + Ion Laser BS Confocal Cavity Power Monitor PD GP-IB Bus PD Absorption Cell (White Cell) L Osc. Block Diagram of The Ti:Sapphire Ring Laser Spectrometer.

6 Recorder Trace of the Absorption Lines in cm -1 Region

7 Fortrat Diagram of I 35 Cl I 35 Cl v’ v” P,Q,R-Blanches Only Q-Blanches v” cm -1

8 I 35 Cl I 35 Cl v’=0-7 T’ 0,T’ 1,,T’ 7 B’ 0e,B’ 1e,,B’ 7e B’ 0f,B’ 1f,,B’ 7f D’ 0,D’ 1,,D’ 7 H’ 0,H’ 1,,H’ 7 I 35 Cl I 35 Cl v’=0-7 T’ 0,T’ 1,,T’ 7 B’ 0e,B’ 1e,,B’ 7e B’ 0f,B’ 1f,,B’ 7f D’ 0,D’ 1,,D’ 7 H’ 0,H’ 1,,H’ 7 I 37 Cl I 37 Cl v’=0-6 T’ 0,T’ 1,,T’ 6 B’ 0e,B’ 1e,,B’ 6e B’ 0f,B’ 1f,,B’ 6f D’ 0,D’ 1,,D’ 6 H’ 0,H’ 1,,H’ 6 I 37 Cl I 37 Cl v’=0-6 T’ 0,T’ 1,,T’ 6 B’ 0e,B’ 1e,,B’ 6e B’ 0f,B’ 1f,,B’ 6f D’ 0,D’ 1,,D’ 6 H’ 0,H’ 1,,H’ 6 I 35 Cl / I 37 Cl Y 10 ’’, Y 20 ’’, Y 30 ’’ Y 01 ’’, Y 11 ’’, Y 21 ’’ Y 02 ’’, Y 12 ’’ Y 03 ’’, Y 13 ’’ I 35 Cl / I 37 Cl Y 10 ’’, Y 20 ’’, Y 30 ’’ Y 01 ’’, Y 11 ’’, Y 21 ’’ Y 02 ’’, Y 12 ’’ Y 03 ’’, Y 13 ’’ The Coefficients of the Power Expansion for the A and the X State

9 The Spectroscopic Constants of The X State In cm -1 and 2.5  in parentheses  = cm -1 Y’’ Y’’  = cm -1 1) Type B ( constrain Y’’ 10 and Y’’ 01 ) Type A (All parameter is variable.) H.G.Heddrich and P.F.Bernath,J.Mol.Spectrosc (1992)  = cm -1 2)Y’’ 03 is calculated using Type C ( constrain Y’’ 10, Y’’ 01 and Y’’ 03 )

10 The Spectroscopic Constants of The A State I 35 Cl I 37 Cl

11 Relationship between Tv and Vibrational Level T’ v v I 37 Cl I 35 Cl

12 Deviation of Tv from the ( v +1/2) Polynomial I 35 Cl I 37 Cl TvTv v

13 Relationship between Bvf and Qv and Vibrational Level

14 Relationship between Dv and Hv and Vibrational Level D’ v x10 8 I 35 Cl I 37 Cl v H’ v x10 13 I 35 Cl I 37 Cl v

15 Average Line Splittings of Vibrational Level in the P- and R-Branches cm -1

16 Summary A – X system of P,Q,R-branch lines were assigned.  4900 lines X-state of Dunham coefficients were determined by using a mass-reduced least square fitting procedure.  7 parameters Spectroscopic constants of A-state were calculated.  Tv, Bvf, qv, Dv, Hv for each vibrational levels (Dunham coefficients are not suitable for A- state.)