molecular spectroscopy symposium 2007 18-22 june 2007 the v t =1 state of methanol john c. pearson,...

Molecular Spectroscopy Symposium 2007 18-22 June 2007

The vt=1 State of Methanol

John C. Pearson, Carolyn Brauer, Brian J Drouin, & John C. Pearson, Carolyn Brauer, Brian J Drouin, & Herbert PickettHerbert Pickett

Jet Propulsion Laboratory, California Institute of Technology, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109Pasadena, CA 91109

Jonathan Fisher, Hongyu Shi, & Li-Hong XuJonathan Fisher, Hongyu Shi, & Li-Hong XuCentre for Laser, Atomic and Molecular Sciences (CLAMS), Centre for Laser, Atomic and Molecular Sciences (CLAMS),

Department of Physical Sciences, University of New Brunswick, Saint Department of Physical Sciences, University of New Brunswick, Saint John, N.B., Canada E2L 4L5John, N.B., Canada E2L 4L5

2Molecular Spectroscopy Symposium 2007 18-22 June 2007

MotivationMotivation

Methanol is insufficiently known for astrophysics!– Was use to test Herschel HIFI instrument to 1.9 THz ~6000 spectra

– Will ultimately extract calibration parameters need synthetic spectra


Previous vPrevious vtt=1 Methanol=1 Methanol

Predictions from Anderson et al., Xu et al. are significantly off for some b-types not in analysis and high J & K transitions

– Fit constrained by IR data if at all

– Fits limited to J<20 data

No published predictions >1 THz

– Need to make assignments and de-bug line list for global fit

Vt=1 has the most problems of the lowest 4 states

– Low K E-state level crossings

– Interactions with vt=0 & 2

– Accidental degeneracy of K levels


Data and SpectrometerData and Spectrometer

Data Set– Complete spectrum 8-540 GHz, 582-702 GHz, 767-965 GHz, 1056-1200 GHz, 1575-1654 GHz

– Some Pieces in the 540-582 GHz

– Some Pieces between 1654-2530 GHz

Most taken with direct multiplication spectrometer at JPL


Data Set A statesData Set A states

Vt=2

K=0 K=1 K=2 K=3 K=4 K=5 K=6 K=7 K=8 K=9 K=10 K=11 K=12 K=13 K=14

Vt=124

P24

R1Q10

46 44

R21Q38

P60

R14Q12

P34

42

R0Q8

P35

R2Q12

38 34

P44

R6Q28

P42

32

R18Q6

P0

32

P22

R4Q44

20P24

R24Q40

22

R10Q20

P822

P2

R0Q0

24P20

R2Q22

24 14 18P0

R0Q0

P0

R0Q0

78 32

21 1218

6 12102 20

13

65

212 4

222 6

Vt=1

Vt=0

K=0 K=1 K=2 K=3 K=4 K=5 K=6 K=7 K=8 K=9 K=10 K=11 K=12 K=13 K=14


A-State PathologiesA-State Pathologies

K=1 crosses vt=0 K=8 spectra assigned to J=41

– Large delta K no significant effect

K=5 is strongly resonant with vt=0 K=9 cross at J=30

– K/torsional state assignment questionable above J=29

K=8 on top of K=1 of vt=2, nearly degenerate with K=9 of vt=1

– Few MHz of impact around J=28

K=9 crosses K=1 of vt=2 at J=27, nearly degenerate with K=8 of vt=1

– K=8 & 9 do not fit

K=13 is strongly resonant with vt=0 K=15 and vt=2 K=11


Vt=1 K=1 & vt=0 K=8Vt=1 K=1 & vt=0 K=8

A levels relative to K=0, vt=1

-72

-71

-70

-69

-68

-67

-66

-65

0 5 10 15 20 25 30 35

J

En

erg

y

Vt=0 K=8

Vt=1 K=1

Levels Cross with little effect in the spectra


Vt=1 K=5 and Vt=0 K=9Vt=1 K=5 and Vt=0 K=9


-4

-3

-2

0 5 10 15 20 25 30 35

J

En

erg

y

Vt=1 K=5

Vt=0 K=9Vt=1 K=5?

Levels cross at J=30 transitions between vt=1 K=4 and vt=0 K=9 levels found


Vt=1 K=8 & 9 and Vt=2 K=1Vt=1 K=8 & 9 and Vt=2 K=1


175

176

177

178

179

180

181

0 5 10 15 20 25 30 35

J

En

erg

y Vt=1 K=8

Vt=1 K=9

Vt=2 K=1

Large Delta K interaction but some apparent effect on K=8 and 9 transitionsproblems at and above crossing


Vt=1 K=13, Vt=0 K=15 and Vt=2 K=11 MessVt=1 K=13, Vt=0 K=15 and Vt=2 K=11 Mess


475

476

477

478

479

480

481

482

483

484

485

0 5 10 15 20 25 30 35

J

En

erg

y

vt=2 K=11

vt=0 K=15

vt=1 K=13

Mixed levels give rise to extra torsional transitions between states


Data set E state vt=1 to vt=1Data set E state vt=1 to vt=1

bR R0 R0 R2 R0 R8 R0 R8 R6 R2 R6 R2 R4 R1 R3bQ Q6 Q0 Q0 Q0 Q29 Q0 Q0 Q27 Q29 Q0 Q19 Q33 Q24 Q11aR 4 8 9 10 13 15 16 17 18 18 20 21 21 21 24bP P6 P0 P0 P10 P15 P7 P2 P23 P28 P2 P24 P28 P27 P5K -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0

bR R19 R11 R12 R3 R2 R4 R9 R9 R1 R1 R7 R0 R0 R0 bQ Q45 Q3 Q26 Q26 Q5 Q2 Q13 Q33 Q1 Q0 Q30 Q0 Q0 Q0aR 24 23 22 18 20 17 18 17 16 15 12 12 8 8 4 bP P26 P15 P22 P23 P17 P1 P20 P16 P2 P0 P14 P12 P0 P0 K 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Data set vt=1 to vt=1

|K|>12 still requires some more attention. Higher J lines are in data but have not been systematically assigned


E-State data set vt=1 to vt=0 &2E-State data set vt=1 to vt=0 &2

-14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0

13 1 7 758 1128

1 4 1 1 311 2 2

Vt=2

Vt=1

Vt=0

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

2 822

3 112

4 8 12

6 31

2 1

Vt=2

Vt=1

Vt=0


E-State PathologiesE-State Pathologies

Low K crossings

– K=-1 & K=3 are strongly resonant at J=29 K=-4 vt=1 and K=9 vt=0 are also involved

– K=-2 and K=4 are strongly resonant at J=34

Torsional interactions

– K=-3 vt=1 and K=-8 vt=0 cross at J=21

– K=9 vt=1 and K=0 vt=2 cross at J=30 Vt=0 K=12 interacts at high J with K=9 vt=1

Remainder of states relatively well isolated so levels followed to J=34+

– |K|>12 requires more analysis data is currently tentative


Vt=1 K=3 & -1 et al.Vt=1 K=3 & -1 et al.

K=-1 vt=0

K=3 vt=0

K=2 vt=1

K=-4 vt=0

K=-9 vt=0

K=9 vt=0

Vt=1 K=3 & K=-1 are strongly resonantK=3 eventually interacts with vt=0 K=9 and vt=1 K=-4 at high J


K=-2 and K=4 vt=1K=-2 and K=4 vt=1

K=-2 vt=1

K=4 vt=1

Vt=1 K=-2 and vt=1 K=4 are strongly resonant at J=33 and 34


K=-3 vt=1 and K=-8 vt=0K=-3 vt=1 and K=-8 vt=0

Vt=0 K=-8

Vt=1 K=-3

Vt=1 K=-3 and vt=0 K=-8 interact weakly does not really affect spectra


K=9 vt=1, K=12 vt=0 & K=0 vt=2K=9 vt=1, K=12 vt=0 & K=0 vt=2

K=9 vt=1

K=12 vt=0

K=0 vt=2

Vt=1 K=9 interacts weakly with vt=2 K=0 andStrongly with vt=0 K=12 at high J


Next StepsNext Steps

Completed power series fits |K|</=12 in E state

– Assign transitions in well behaved K states to higher J, J~45

Complete power series fits of |K|>12

Complete power series fits of ground state E

– Problems with low K interactions

Assign additional torsional transitions at high J

Fit with IAM Hamiltonian that will predict level crossings

– Predict frequencies on the other side of crossings

– Assign transitions & repeat fit & do quantum mechanics as necessary

Measure dipole moment as function of K & vt

Compare with HIFI spectrum

Talk on Friday about initial step in IAM fitting of data set

molecular spectroscopy symposium 2007 18-22 june 2007 the v t =1 state of methanol john c. pearson,...

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