Millimeter- Wave Spectroscopy of Hydrazoic acid (HN3)
Brent K. Amberger, Brian J. Esselman,
R. Claude Woods, Robert J. McMahon
University of Wisconsin
June 18, 2014
Previous Work on HN3
1930’s
Herzberg, G.; Patat, F.; Verleger, H., Z. Elektrochem. Angew. Phys. Chem.
1935, 41, 522-4.
1960’s- 1970’s
Kewley, R.; Sastry, K. V. L. N.; Winnewisser, M., Journal of Molecular Spectroscopy 1964,
12, 387-401.
Bendtsen, J.; Winnewisser, M., Chemical Physics Letters 1975, 33, 141-145.
Bendtsen, J.; Winnewisser, M., Chemical Physics 1979, 40, 359-365.
1980’s- 1990’s
Bendtsen, J.; Hegelund, F.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1986, 118, 12.
Hegelund, F.; Bendtsen, J., Journal of Molecular Spectroscopy 1987, 124, 306-316.
Bendtsen, J.; Hegelund, F.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1988, 128, 309-320.
Bendtsen, J.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1991, 145, 123-129.
Bendtsen, J.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1992, 152, 101-108.
Bendtsen, J.; Guelachvili, G., Journal of Molecular Spectroscopy 1994, 165, 159-167.
Hansen, C. S.; Bendtsen, J.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1996, 175, 239-245.
The Synthesis
To Spectrometer
Dry Ice Trap
Access to:
HNNN
DNNN
H15NNN / HNN15N
D15NNN / DNN15N
H2O or D2O
NaN3
or
Na15NNN
Our Spectrometer
~260-360 GHz range
20 mTorr sample
Room temperature
CCSD(T)/ANO2 Structure
b
1.244 Å
171.65°
1.017 Å
108.71 °
1.132 Å
a
Predicted Spectra for HN3 and DN3
HN3
DN3
Our Range
R- Series Anatomy HN3
K=0
J = 13  12
K=1
K=1
K=2
K=3
K=4
K=7
K=6
K=5
The Spectrum: Full Range 235-360 GHz
J = 10  9
J = 11  10
J = 12  11
J = 13  12
J = 14  13
J = 15  14
The Spectrum: Key Features
HN3
J = 13  12
11 1 11  12 0 12
K=1
K=0
K=1
35 0 35  34 1 34
HNN15N
H15NNN
J = 13  12 J = 13  12
Vibrationally
excited modes
The Spectrum: H15NNN
H15NNN at natural isotopic abundance
K=5
K=4
K=2
J = 13  12
K=3
K=2
K=0
Finding Naturally Occurring Center 15N
Loomis- Wood plots centered on H14N3 lines were used to find corresponding HN15NN lines
The fit data: HN3
Bendtsen and
Winnewisser
1975 (MHz)
Present Work
(MHz)
CCSD(T)/ANO2
(MHz)
A
610996.2 (6.0)
610766.49 (46)
605072
B
12034.1465(50)
12034.951(47)
11989
C
11781.4512(50)
11780.700(48)
11737
DJ
0.004673(35)
0.0049185(33)
0.00475
DJK
0.7911858(11)
0.79676(21)
0.904
DK
[230]
[0]
224
dj
0.0000888(27)
0.00009045(54)
0.0000769
dk
[0]
0.388(23)
0.379
HJ
0.000000088(36)
-0.0000000037(13)
HJK
0.0000406(86)
0.00000144(17)
HKJ
-0.001210(35)
0.000135(20)
HK
[0]
[0]
LKKJ
-0.00003712(55)
Bendtsen, J.; Winnewisser, M., Chemical Physics Letters 1975, 33, 141-145.
Summary of Isotopologues
HNNN
H15NNN
HN15NN
HNN15N
H15N15NN
H15NN15N
HN15N15N
A
(MHz)
610766.491(46)
605313.25(68)
609767.695(52)
610709.650(89)
601081.(730)
603383.(332)
?
B
(MHz)
12034.951(47)
11668.9(11)
12034.147(21)
11642.534(49)
11666.735(83)
11283.234(42)
?
C
(MHz)
11780.700(48)
11426.4(11)
11779.488(21)
11404.322(49)
11424.417(81)
11057.174(41)
?
n
110
74
58
62
45
61
4?
DNNN
D15NNN
DN15NN
DNN15N
D15N15NN
D15NN15N
DN15N15N
A
(MHz)
344746.666(24)
340247.371(21)
344527.615(51)
344727.850(25)
340007.070(18)
340145.581(18)
344511.062(32)
B
(MHz)
11350.9654(26)
11045.7287(31)
11347.9000(67)
10980.1221(31)
11042.005(11)
10680.229(13)
10979.119(19)
C
(MHz)
10964.8155(27)
10675.2595(25)
10963.1789(67)
10618.3330(27)
10671.754(12)
10333.591(13)
10617.349(18)
n
162
136
86
134
67
83
57
Cannot access H15N15N15N or D15N15N15N
Re Structure Determination
Experimental constants were corrected for vibrationrotation interaction and electron mass.
b
Using xrefit module in CFOUR:
Fit 5 structural parameters to 39 moments of inertia.
a
1.1290(15) Å
108.976(64)°
1.01559(63) Å
171.14(19)°
1.2438(14) Å
Structure Comparison
CCSD(T)/ANO2
(Re)
xrefit (Re)
Substitution
Structure (Rs)
R1 (Å)
1.133
1.1290(15)
1.159(50)
R2 (Å)
1.245
1.2438(14)
1.204(61)
R3 (Å)
1.017
1.01559(63)
1.017(12)
A1
108.71°
108.976°(64)
108.0°(21)
A2
171.65°
171.14°(19)
171.26°(57)
R1
R2
A2
A1
R3
Excited Vibrational States
1266.63 cm-1
~1213 cm-1
1147.40 cm-1
~1143.5 cm-1
HN3
~1074 cm-1
2ν5
ν6
606.36 cm-1
537.25
cm-1
ν3
2ν6
ν4
ν5+ ν6
Coriolis perturbation
ν5
Centrifugal
distortion
perturbation
0 cm-1
DN3
1197.39 cm-1
1162.42 cm-1
ν3
2ν6
~1082 cm-1
ν5+ ν6
~991 cm-1
954.77 cm-1
2ν5
ν4
ν6
586.49 cm-1
495.74
cm-1
Coriolis perturbation
ν5
Centrifugal
distortion
perturbation
Ground
0 cm-1
Ground
Past IR Work
-A large body of work analyzing each rotationally-resolved band in HN3 and
DN3 IR spectra has been published.
-Rotational constants and coupling terms from IR data has been published.
-Published data does not adequately predict lines for vibrationally excited
states in our millimeter-wave spectra.
-The published data is still an outstanding starting point for our own analysis.
For our analysis of ν5 and ν6 the literature gives us starting points for the
rotational constants and 3 separate Coriolis terms: Za, ηbc and Zb. Also
provides very accurate energy separation between states.
The published high-resolution rovibrational transitions allow us to calculate
where the pure rotational transitions should be.
Hegelund, F.; Bendtsen, J., Journal of Molecular Spectroscopy 1987, 124, 306-316.
Bendtsen, J.; Hegelund, F.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1988, 128, 309-320.
Finding HN3 ν5 13 3 10 – 12 3 9
ν5
13 3 10
13 3 10
12 3 9
12 3 9
14 3 11
13 3 10
Ground
12 3 9
11 3 8
Error of 0.001 cm-1 = 30 MHz
Calculated from R- branch IR transitions Calculated from P- branch IR transitions
309933 MHz
309937 MHz
Initial Assignments of ν5 and ν6 Lines
Calculated from R-branch
IR transitions
Calculated from P-branch
IR transitions
Initial Assignments of ν5 and ν6 Lines
Lines assigned based on rovibrational transitions
Fit for States ν5 and ν6 of HN3
Actual Fit!
Combined fit for ν5 and ν6 of HN3
ν5
Present Work
Hegelund et al.
1987
ν6
Present Work
Hegelund et al.
1987
A
675700 (2800)
590240(19)
A
739181(3458)
623487(19)
B
12073.79 (30)
12061.76(66)
B
12039.160(271)
12029.44(66)
C
11778.56 (30)
11790.63(66)
C
11797.462(271)
11807.30(66)
Present Work
Hegelund et al.
1987
Za
1.2434(32)*106
[1.141*106]
ηbc
9.30 (19)
9.65(24)
Zb
1828.2 (30)
1874.3(39)
E
[2071299]
[2071299]
Combined fit for ν5 and ν6 of DN3
ν5
Present Work
Hegelund et
al 1987
ν6
Current
Hegelund et al
1987
A
340411.947(17)
327613(12)
A
342198.19 (14)
361742(36)
B
11387.10792(11)
11386.33(57)
B
11350.58853 (84)
11348.31(57)
C
1097.530533(97)
10971.95(57)
C
10985.59915 (66)
10987.36(57)
Present Work
Hegelund et al
1987
Za
595173.573(42)
[565409]
ηbc
4.62773(12)
4.80(90)
Zb
1382.399(79)
2130(180)
E
[2720661.5]
[2720661.5]
Summary and Ongoing Work
Accomplished:
1.1290(15) Å
Best structure of HN3 to date.
108.976(64)°
1.01559(63) Å
Combined fits for Coriolis coupled
ν5 and ν6 states.
171.14(19)°
1.2438(14) Å
In Progress:
Find more lines, especially B-type lines to tighten up the fits.
Investigate the complex coupling patterns of the higher energy vibrationally excited states.
Thanks for Listening!
McMahon group + R.C. Woods