Recent results we are most excited about and recent publications

 

Below: Schematic diagram of the TAMU fast scan submillimeter-wave spectrometer with phase locked BWO and a coaxial pulsed supersonic jet.
Right: Static gas phase Lamb-dip spectrum of 2H79Br J= 1←0 transition with unresolved deuterium hyperfine F1',F',F1", F"; 1/2, 3/2 ← 3/2, 1/2, 3/2, 5/2 components( 254 571.6545(15), 254 571.6593(15) MHz) recorded at 1 mTorr total pressure.

 

Right: Submillimeter-wave supersonic jet spectrum of 2H79Br J= 1←0, with unresolved deuterium hyperfine F1',F' - F1", F"; 5/2, 3/2; 5/2,7/2 ← 3/2, 1/2, 3/2, 5/2 ((254 678.3362(15), 254 678.3442(10) MHz respectively) transitions partially resolved from the 5/2,5/2, ← 3/2, 1/2, 3/2, 5/2 components (254 678.3785(5) MHz) (Quoted transition frequencies from reference 13)

 

 

Right: A round trip frequency scan of the F=11/29/2 R(3) transition in Ar:H81Br illustrating Doppler displaced components.

 

Table 1 Accuracy of absolute frequency measurement of J=1←0, F=1/23/2 transition of 2H79Br with the TAMU fast scan submm-wave spectrometer with a coaxial pulsed jet. fL is the Lamb-dip measured frequency and fD = 254 571.6577(15) MHz is the weighted frequency.

 

Pulse Jet Expansion

fo (MHz)

Static Cell

fo - fL (MHz)

Molecular Beam

fo - fD (MHz)

254571.6574

-0.0011

-0.0003

254571.6576

-0.0009

-0.0001

254571.6581

-0.0004

+0.0004

254571.6578

-0.0007

+0.0001

254571.6545(15)a

 

 

254571.6593(15)a

 

 

 

a Measured by F.A. Van Dijk and A. Dymanus, Chem. Phys. 6 474 (1974). 13

 

Rovibrational Molecular Spectroscopy with Accuracy and Precision Compared to Highest Resolution and Most Accurate Pulsed-Nozzle FT Microwave Spectrometer (1.5 kHz (5x10-8 cm-1), accuracy 200 Hz(7x10-9 cm-1))

Table 2 Combination frequency differences of submillimeter-wave and corresponding sum frequencies from microwave transitions for Ar:H79Br and Ar:H81Br. All transitions frequencies are in units of MHz.

 

Microwave Data

Submillimeter Data

 

J,F

f(J,F)a

f(J+1,F+1)

f(J,F) + f(J+1,F+1)

fR(J,F)b

fP(J+2,F+2)c

fR(J,F) fP(J+2,F+2)

Differenced

Ar:H79Br

 

 

 

 

 

 

 

2,

6647.38485

8853.86864

15501.25349

337798.3503

322297.0960

15501.2543

0.00081

2,

6647.23095

8853.85453

15501.08548

337820.0836

322318.9970

15501.0866

0.00112

2,

6636.64188

8848.89459

15485.53647

337819.4418

322333.9053

15485.5365

0.00003

2,

6636.63578

8848.87148

15485.50726

337797.6296

322312.1230

15485.5066

-0.00066

3,

8853.86864

11062.52265

19916.39129

341044.6861

321128.2946

19916.3915

0.00021

3,

8853.85453

11062.54665

19916.40118

341066.4112

321150.0103

19916.4009

-0.00028

3,

8848.89459

11059.61550

19908.51009

341068.9003

321160.3902

19908.5101

0.00001

3,

8848.87148

11059.57871

19908.45019

341047.1800

321138.7307

19908.4493

-0.00089

4,

11062.52265

13270.60769

24333.13034

344551.8020

320218.6725

24333.1295

-0.00084

4,

11062.54665

13270.65077

24333.19742

344573.4231

320240.2263

24333.1968

-0.00062

4,

11059.61550

13268.69975

24328.31525

344576.4543

320248.1391

24328.3152

-0.00005

4,

11059.57871

13268.65213

24328.23084

344554.8511

320226.6206

24328.2305

-0.00034

Ar:H81Br

 

 

 

 

 

 

 

2,

6591.43430

8780.60063

15372.03493

337352.9207

321980.8838

15372.0369

0.00197

2,

6591.32966

8780.59531

15371.92497

337371.0415

321999.1158

15371.9257

0.00073

2,

6582.45982

8776.44197

15358.90179

337370.4929

322011.5889

15358.9040

0.00221

2,

6582.45370

8776.42108

15358.87478

337352.3195

321993.4448

15358.8747

-0.00008

3,

8780.60063

10971.39779

19751.99842

340577.2026

320825.2034

19751.9992

0.00078

3,

8780.59531

10971.42045

19752.01576

340595.3066

320843.2911

19752.0155

-0.00026

3,

8776.44197

10968.96606

19745.40803

340597.3825

320851.9751

19745.4074

-0.00063

3,

8776.42108

10968.93484

19745.35592

340579.2856

320833.9299

19745.3557

-0.00022

4,

10971.39779

13161.50034

24132.89813

344060.7539

319927.8561

24132.8978

-0.00033

4,

10971.42045

13161.53718

24132.95763

344078.7711

319945.8133

24132.9578

0.00017

4,

10968.96606

13159.90410

24128.87016

344081.3036

319952.4333

24128.8703

0.00014

4,

10968.93484

13159.86411

24128.79895

344063.3031

319934.5048

24128.7983

-0.00065

 

a Measured frequency of microwave transitions DJ=+1 DF=+1.

b Measured frequency of ro-vibrational transitions with DJ=+1 DF=+1

c Measured frequency of ro-vibrational transitions with DJ= 1 DF= 1

a The difference is [fR(J,F) - fP(J+2,F+2)] - [f(J,F) + f(J+1,F+1)]

ΔF = +/-1 Transition Comparison Avoids Effects of H.Br Spin-Spin Coupling Splitting (Hydrogen Hyperfine Splitting) for Ar:HBr(Measurements made Independently at TAMU and University of Exeter, England)

Table 3 Fitted Parameters for Ar:H79Br and Ar:H81Br

 

 

n0 (MHz)

B (MHz)

DJ (kHz)

HJ (MHz)

cR (MHz)

cJ (kHz)

Mbb (kHz)

Ar:H79Bra

329611.4298(3)

1236.4133600(500)

12.46230(230)

-2.6901(402)e-6

260.39770(80)

-31.6084(304)

1.9551(313)

Ar:H79Brb

 

1106.6712300(600)

12.50180(350)

1.7087(728)e-6

173.22710(90)

17.4494(342)

0.6541(323)

Ar:H79Brc

 

1106.6713099(270)

12.50219(129)

1.6693(187)e-6

173.22878(53)

17.4340(260)

0.5644(280)

Ar:H79Brd

 

1106.66951(17)

12.39(4)

 

173.199(6)

18.42(26)

 

Ar:H81Bra

329225.6797(3)

1226.7733500(600)

12.29470(270)

-2.7239(469)e-6

217.89830(100)

-26.2603(331)

1.9946(350)

Ar:H81Brb

 

1097.5819900(700)

12.30160(410)

1.6766(866)e-6

144.80740(100)

14.5452(373)

0.6738(354)

Ar:H81Brc

 

1097.5819815(287)

12.29802(132)

1.5982(188)e-6

144.81000(53)

14.5153(267)

0.6204(284)

Ar:H81Brd

 

1097.58109(15)

12.26(3)

 

144.793(5)

15.2(23)

 

 

a S bending vibrational state parameters from submillimeter-wave data.

b Ground state parameters from submillimeter-wave data.

c Ground state parameters from microwave FT data.

d Ground state parameters from M.R. Kennan, E.J. Campbell, T.J. Balle, L.W. Buxton, T.J. Munton, P.D. Sopevand, W.H. Flugare, J. Chem. Phys 72 3070 (1980). 9

 


Conclusions