1887
banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
f
Microwave measurements of proton tunneling and structural parameters for the propiolic acid–formic acid dimer
Rent:
Rent this article for
Access full text Article
/content/aip/journal/jcp/135/15/10.1063/1.3643720
1.
1. S. Scheiner and C. W. Kern, J. Am. Chem. Soc. 101, 4081 (1979).
http://dx.doi.org/10.1021/ja00509a012
2.
2. P. O. Löwdin, Adv. Quantum Chem. 2, 213 (1965).
http://dx.doi.org/10.1016/S0065-3276(08)60076-3
3.
3. J. Catalan and M. Kasha, J. Phys. Chem. A 104, 10812 (2000).
http://dx.doi.org/10.1021/jp0028397
4.
4. F. Madeja and M. Havenith, J. Chem. Phys. 117, 7162 (2002).
http://dx.doi.org/10.1063/1.1507581
5.
5. A. Gutberlet, G. W. Schwaab, and M. Havenith, Chem. Phys. 343, 158 (2008).
http://dx.doi.org/10.1016/j.chemphys.2007.08.025
6.
6. O. Birer and M. Havenith, Annu. Rev. Phys. Chem. 60, 263 (2009).
http://dx.doi.org/10.1146/annurev.physchem.040808.090431
7.
7. M. C. D. Tayler, B. Ouyang, and B. J. Howard, J. Chem. Phys. 134, 054316 (2011).
http://dx.doi.org/10.1063/1.3528688
8.
8. A. M. Daly, P. R. Bunker, and S. G. Kukolich, J. Chem. Phys. 132(20), 2011011 (2010);
http://dx.doi.org/10.1063/1.3443508
8.A. M. Daly, P. R. Bunker, and S. G. Kukolich, J. Chem. Phys. 133(7), 0799031 (2010).
http://dx.doi.org/10.1063/1.3472345
9.
9. B. S. Jursic, J. Mol. Struct. 417, 99 (1997).
http://dx.doi.org/10.1016/S0166-1280(97)00052-3
10.
10. N. Shida, P. F. Barbara, and J. Almlöf, J. Chem. Phys. 94, 3633 (1991).
http://dx.doi.org/10.1063/1.459734
11.
11. W. Siebrand, Z. Smedarchina, and A. F. Fernandez-Ramos, Chem. Phys. Lett. 459, 22 (2008).
http://dx.doi.org/10.1016/j.cplett.2008.04.131
12.
12. H. M. Pickett, J. Chem. Phys. 56, 1715 (1972).
http://dx.doi.org/10.1063/1.1677430
13.
13. H. M. Pickett, J. Mol. Spectrosc. 148, 371 (1991); see also (http://spec.jpl.nasa.gov/ftp/pub/calpgm/spinv.html).
http://dx.doi.org/10.1016/0022-2852(91)90393-O
14.
14. S. L. Baughcum, Z. Smith, E. B. Wilson, and R. W. Durest, J. Am. Chem. Soc. 106, 2260 (1984).
http://dx.doi.org/10.1021/ja00320a007
15.
15. K. Tanaka, H. Honjo, T Tanaka, H. Kohguchi, Y. Ohshima, and Y. Endo, J. Chem. Phys. 110, 1969 (1999).
http://dx.doi.org/10.1063/1.477863
16.
16. M. J. Frisch, G. W. Trucks, H. B. Schlegel, et al., GAUSSIAN 03, Revision A.1, Gaussian, Inc., Wallingford, CT, 2009.
17.
17. C. Lee, W. Yang, and R. G. Parr, Phys. Rev. B 37, 785 (1988).
http://dx.doi.org/10.1103/PhysRevB.37.785
18.
18. J. P. Perdew, K. Burke, and Y. Wang, Phys. Rev. B 54, 16533 (1996).
http://dx.doi.org/10.1103/PhysRevB.54.16533
19.
19. A. D. Boese and N. C. Handy, J. Chem. Phys. 114, 5497 (2001).
http://dx.doi.org/10.1063/1.1347371
20.
20. J. Tao, J. P. Perdew, V. N. Staroverov, and G. E. Scuseria, Phys. Rev. Lett. 91, 146401 (2003).
http://dx.doi.org/10.1103/PhysRevLett.91.146401
21.
21. B. S. Tackett, C. Karunatilaka, A. Daly, and S. G. Kukolich, Organometallics 26, 2070 (2007).
http://dx.doi.org/10.1021/om061027f
22.
22. S. G. Kukolich and L. C. Sarkozy, Rev. Sci. Instrum. 82, 094103 (2011).
http://dx.doi.org/10.1063/1.3627489
23.
23. T. J. Balle and W. H. Flygare, Rev. Sci. Instrum. 52, 33 (1981).
http://dx.doi.org/10.1063/1.1136443
24.
24. R. D. Suenram, J. U. Grabow, A. Zupan, and I. Leonov, Rev. Sci. Instrum. 70, 2127 (1999).
http://dx.doi.org/10.1063/1.1149725
25.
25. M. Nakajima, Y. Sumiyoshi, and Y. Endo, Rev. Sci. Instrum. 73, 165 (2002).
http://dx.doi.org/10.1063/1.1426230
26.
26. G. G. Brown, B. C. Dian, K. O. Douglass, S. M Geyer, S. T Shipman, and B. H. Pate, Rev. Sci. Instrum. 79, 0531031 (2008).
http://dx.doi.org/10.1063/1.2919120
27.
27. T. Emilsson, H. S. Gutowsky, G. de Oliveira, and C. E. Dykstra, J. Chem. Phys. 112, 1287 (2000).
http://dx.doi.org/10.1063/1.480680
28.
28. A. Bauder, J. Mol. Struct. 408/409, 33 (1997).
http://dx.doi.org/10.1016/S0022-2860(96)09492-6
29.
29. D. G. Lister and J. K. Tyler, Spectrochim. Acta A 28, 1423 (1972).
http://dx.doi.org/10.1016/0584-8539(72)80111-9
30.
30. J. Bellet, A. Deldalle, C. Samson, G. Steenbeckeliers, and R. Wetheimer, J. Mol. Structure 9, 65 (1971).
http://dx.doi.org/10.1016/0022-2860(71)85007-X
31.
31. L. Martinache, W. Kresa, M. Wegener, U. Vonmont, and A. Bauder, Chem. Phys. 148, 129 (1990).
http://dx.doi.org/10.1016/0301-0104(90)89013-G
33.
33. K. Tanaka, T. Tanaka, and I. Suzuki, J. Chem. Phys. 82, 2835 (1985).
http://dx.doi.org/10.1063/1.448285
34.
34. P. R. Bunker and P. Jensen, Molecular Symmetry and Spectroscopy (NRC Research Press, Ottawa, 1998).
35.
35. J. M. Hollas, High Resolution Spectroscopy (Wiley, New York, 1998).
http://aip.metastore.ingenta.com/content/aip/journal/jcp/135/15/10.1063/1.3643720
Loading

Figures

Image of FIG. 1.

Click to view

FIG. 1.

Structure of the Pro-FA complex from the calculations using MP2/6-311++G**.

Image of FIG. 2.

Click to view

FIG. 2.

Diagram of the large-cavity, pulsed-beam Fourier transform spectrometer (Arizona). (1) Microwave synthesizer hp 8665B, (2) power divider, (3) SPDT microwave switch, (4) microwave cavity, 48 diameter mirrors, (5) low-noise microwave amplifier MITEQ, (6) microwave mixer, (7) Stanford Research Systems preamplifier, (8) multichannel digitizer PICO ADC-212/50.

Image of FIG. 3.

Click to view

FIG. 3.

The 1731.834 MHz line of the propiolic–formic acid complex (average of 35 000 pulses), data taken with the large-cavity, FTMW spectrometer (Arizona).

Image of FIG. 4.

Click to view

FIG. 4.

The FTMW-pulsed-MW double resonance spectra are shown for the pure rotational transition 7070-6060 centered at 11 997.3572 MHz (black) and the tunneling-rotation transition 7170+-6060 centered at 15 347.5405 MHz (grey). The center frequency of each double resonance spectrum was subtracted to put both double resonance peaks at 0 frequency. This was done to directly compare the linewidths of the two measurements. The linewidth is an indicator of line strength. These measurements were performed by monitoring the amplitude of 6060-5050 (10 311.3665 MHz) rotational transition with the FTMW cavity, while the pump frequency of a second microwave source, radiated from a standard gain horn, was scanned across the desired rotational transition with 10 averages at each step and 10 kHz step size for tunneling-rotation transitions. For both spectra the double resonance pulse had a duration of 5 μs and a power level of 7.3 W.

Image of FIG. 5.

Click to view

FIG. 5.

The 0 (a) and 0+ (b) tunneling doublets for the 707-606 pure rotational transitions and the (c) 6060 and 7170+ tunneling-rotation transition observed by FTMW spectroscopy are shown. The spectra were recorded with 400 signal averages at a 10 Hz repetition rate. Panels (a) and (b) illustrate the 3:1 intensity ratio for changing vibrational state only.

Image of FIG. 6.

Click to view

FIG. 6.

The alternating 3:1 intensity pattern is observed for the different Ka and vibrational states.

Image of FIG. 7.

Click to view

FIG. 7.

Detection of b-type transitions in the OD/OD isotopologue of formic acid–propiolic acid complex. (a) Microwave-microwave double resonance measurement. The 606-505 transition of the complex was monitored in the FTMW cavity. The double resonance frequency was moved in steps of 50 kHz, and 100 signal averages were acquired at each frequency. The two transitions are each offset by ∼3.4 MHz from the calculated b-type transition frequency without tunneling included. (b) A b-type transition measured in single resonance on the FTMW cavity. For this spectrum, 10 000 signal averages were acquired. The transition is doubled due to the coaxial arrangement of the microwave source and the molecular beam. The transition at slightly lower frequency than the b-type transition is due to a different species in the sample.

Image of FIG. 8.

Click to view

FIG. 8.

Structural fit parameters include the distance between the centers of mass of the monomers (Rc.m.), the angle ɛ, <(C–O4–H2) of formic acid, and the rotation of formic acid about its center of mass, θ.

Image of FIG. 9.

Click to view

FIG. 9.

Dipole moment determination of the formic acid–propiolic acid complex. (a) Calibration of the electric field using OCS. (b) The 515-414 transition of formic acid–propiolic acid, showing the spectrum with and without an applied electric field, compared to simulations of the two states using the fit dipole moments.

Image of FIG. 10.

Click to view

FIG. 10.

CP-FTMW spectrum of Pro-FA. The strongest transitions are the a-type pure rotational transitions. The inset shows a b-type tunneling-rotation transition. The relative intensities between the a- and b-type transitions were used to estimate the ratio of the dipole moment components μ a : μ b.

Tables

Generic image for table

Click to view

Table I.

Summary of calculated and experimental key molecular and structural parameters.

Generic image for table

Click to view

Table II.

The measured transitions of Pro-FA from 1.7 GHz to 21.3 GHz.

Generic image for table

Click to view

Table III.

Measured transitions for the dipole moment determination of the 0+ and 0 states of the formic acid–propiolic acid complex, performed with an electric field strength of 464 V/cm. All frequencies are reported in MHz.

Generic image for table

Click to view

Table IV.

Propiolic acid–formic acid (13C) data showing the tunneling splitting pairs. Units are Obs. (MHz), Obs. – calc. (kHz).

Generic image for table

Click to view

Table V.

Measured transitions of ProOD-FAOD. Units are Obs. (MHz), Obs. – calc. (kHz).

Generic image for table

Click to view

Table VI.

Summary of measured transition frequencies (MHz) and fit deviations [Obs. – calc. (kHz)] for the deuterium-substituted isotopologues.

Generic image for table

Click to view

Table VII.

Rotational and distortion constants for measured isotopologues of the propiolic–formic dimer. The square brackets indicate parameters that were fixed to values obtained for the normal isotopologue fit of 0+.a

Generic image for table

Click to view

Table VIII.

Molecular parameters obtained from the global fit of 166 transitions (138 a-type and 28 b-type) proton-proton exchange and 12 transitions (8 a-dipole and 4 b-type) deuterium-deuterium exchange. H–H refers to the normal isotopologue and D–D refers to the isotopomer with D substitution at both hydrogen-bonding sites.a

Generic image for table

Click to view

Table IX.

Summary of results from the structure fits with the propiolic acid C–O–H angle fixed and formic acid C–O–H angle, ɛ, varied. Rc.m. is 3.878(2) Å and θ is +5.0°(2) from the MP2 calculated starting structure (counterclockwise).

Generic image for table

Click to view

Table X.

Key atomic coordinates from the Kraitchman analysis and Structure Fit I. Fit I is a three parameter fit, Rc.m. using θ and ɛ with the propiolic angle < (C–O1–H1) fixed at 106º.a

Loading

Article metrics loading...

/content/aip/journal/jcp/135/15/10.1063/1.3643720
2011-10-19
2014-04-21

Abstract

Microwave spectra of the propiolic acid–formic acid doubly hydrogen bonded complex were measured in the 1 GHz to 21 GHz range using four different Fourier transform spectrometers. Rotational spectra for seven isotopologues were obtained. For the parent isotopologue, a total of 138 a-dipole transitions and 28 b-dipole transitions were measured for which the a-dipole transitions exhibited splittings of a few MHz into pairs of lines and the b-type dipole transitions were split by ∼580 MHz. The transitions assigned to this complex were fit to obtain rotational and distortion constants for both tunneling levels: A0+ = 6005.289(8), B0+ = 930.553(8), C0+ = 803.9948(6) MHz, Δ0+ J = 0.075(1), Δ0+ JK = 0.71(1), and δ0+ j = −0.010(1) kHz and A0− = 6005.275(8), B0− = 930.546(8), C0− = 803.9907(5) MHz, Δ0− J = 0.076(1), Δ0− JK = 0.70(2), and δ0− j = −0.008(1) kHz. Double resonance experiments were used on some transitions to verify assignments and to obtain splittings for cases when the b-dipole transitions were difficult to measure. The experimental difference in energy between the two tunneling states is 291.428(5) MHz for proton-proton exchange and 3.35(2) MHz for the deuterium-deuterium exchange. The vibration-rotation coupling constant between the two levels, Fab, is 120.7(2) MHz for the proton-proton exchange. With one deuterium atom substituted in either of the hydrogen-bonding protons, the tunneling splittings were not observed for a-dipole transitions, supporting the assignment of the splitting to the concerted protontunneling motion. The spectra were obtained using three Flygare-Balle type spectrometers and one chirped-pulse machine at the University of Virginia. Rotational constants and centrifugal distortion constants were obtained for HCOOH···HOOCCCH, H13COOH···HOOCCCH, HCOOD···HOOCCCH, HCOOH···DOOCCCH, HCOOD···DOOCCCH, DCOOH···HOOCCCH, and DCOOD···HOOCCCH. High-level ab initio calculations provided initial rotational constants for the complex, structural parameters, and some details of the protontunneling potential energy surface. A least squares fit to the isotopic data reveals a planar structure that is slightly asymmetric in the OH distances. The formic OH···O propiolic hydrogen bond length is 1.8 Å and the propiolic OH···O formic hydrogen bond length is 1.6 Å, for the equilibrium configuration. The magnitude of the dipole moment was experimentally determined to be 1.95(3) × 10−30 C m (0.584(8) D) for the 0+ states and 1.92(5) × 10−30 C m (0.576(14) D) for the 0 states.

Loading

Full text loading...

/deliver/fulltext/aip/journal/jcp/135/15/1.3643720.html;jsessionid=4tq17cla5dmok.x-aip-live-03?itemId=/content/aip/journal/jcp/135/15/10.1063/1.3643720&mimeType=html&fmt=ahah&containerItemId=content/aip/journal/jcp
true
true
This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Microwave measurements of proton tunneling and structural parameters for the propiolic acid–formic acid dimer
http://aip.metastore.ingenta.com/content/aip/journal/jcp/135/15/10.1063/1.3643720
10.1063/1.3643720
SEARCH_EXPAND_ITEM