MF. Minisymposium: Spectroscopy of Large Amplitude Motions
Monday, 20160620, 01:30 PM
Noyes Laboratory 100
SESSION CHAIR: Isabelle Kleiner (CNRS UMR7583, Université ParisEst Créteil et Université de Paris, Créteil, France)



MF01 
Invited MiniSymposium Talk 
30 min 
01:30 PM  02:00 PM 
P1628: ON THE LOWEST ROVIBRATIONAL STATES OF PROTONATED METHANE:
EXPERIMENT AND ANALYTICAL MODEL 
HANNO SCHMIEDT, I. Physikalisches Institut, University of Cologne, Cologne, Germany; PER JENSEN, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany; OSKAR ASVANY, STEPHAN SCHLEMMER, I. Physikalisches Institut, Universität zu Köln, Köln, Germany; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF01 
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Protonated methane, CH _{5}^{+}, is the prototype of an extremely floppy molecule. To the best of our knowledge all barriers are surmountable in the rovibrational ground state; the large amount of zeropoint vibrational energy leads to large amplitude motions for many degrees of freedom. Low resolution but broad band vibrational spectroscopy [1] revealed an extremely wide range of CH stretching vibrations. Comparison with theoretical IR spectra supported the structural motif of a CH _{3} tripod and an H _{2} moiety, bound to the central carbon atom by a 3c2e bond. In a more dynamic picture the five protons surround the central carbon atom without significant restrictions on the HCH bending or H _{n}C torsional motions. The largeamplitude internal motions preclude a simple theoretical description of the type possible for more conventional molecules, such as the related sphericaltop methane molecule. Recent highresolution rovibrational spectra obtained in cold ion trap experiments [2] show that the observed CH _{5}^{+} transitions belong to a very welldefined energy level scheme describing the lowest rotational and vibrational states of this enigmatic molecule. Here we analyse the experimental ground state combination differences and associate them with the motional states of CH _{5}^{+} allowed by FermiDirac statistics. A model Hamiltonian for unrestricted internal rotations in CH _{5}^{+} yields a simple analytical expression for the energy eigenvalues, expressed in terms of new quantum numbers describing the free internal rotation. These results are compared to the experimental combination differences and the validity of the model will be discussed together with the underlying assumptions.
[1] O. Asvany, P. Kumar, I. Hegemann, B. Redlich, S. Schlemmer and D. Marx, Science 309, (2005) 12191222
[2] O. Asvany, K.M.T. Yamada, S. Brünken, A. Potapov, S. Schlemmer, Science 347 (2015) 13461349


MF02 
Contributed Talk 
15 min 
02:05 PM  02:20 PM 
P1552: SYMMETRY IN THE GENERALIZED ROTOR MODEL FOR EXTREMELY FLOPPY MOLECULES 
HANNO SCHMIEDT, I. Physikalisches Institut, University of Cologne, Cologne, Germany; PER JENSEN, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany; STEPHAN SCHLEMMER, I. Physikalisches Institut, University of Cologne, Cologne, Germany; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF02 
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Protonated methane CH _{5}^{+} is unique: It is an extremely fluxional molecule. All attempts to assign quantum numbers to the highresolution transitions obtained over the last 20 years have failed because molecular rotation and vibration cannot be separated in the conventional way Schmiedt, H., et al.; J. Chem. Phys. 143 (15), 154302 (2015)Wodraszka, R. et al.; J.
Phys. Chem. Lett. 6, 42294232 (2015). The first step towards a theoretical description is to include internal rotational degrees of freedom into the overall ones, which can be used to formulate a fundamentally new zero order approximation for the (now) generalized rotational states and energies. Predictions from this simple fivedimensional rotor model compare very favorably with the combination differences of protonated methane found in recent low temperature experiments Asvany, O. et al.; Science, 347, (6228), 13461349 (2015) This talk will focus on symmetry aspects and implications of permutation symmetry for the generalized rotational states. Furthermore, refinements of the theory will be discussed, ranging from the generalization to even higherdimensional rotors to explicit symmetry breaking and corresponding energy splittings. The latter includes the link to wellknown theories of internal rotation dynamics and will show the general validity of the presented theory.
Footnotes:
Schmiedt, H., et al.; J. Chem. Phys. 143 (15), 154302 (2015)
Footnotes:
Asvany, O. et al.; Science, 347, (6228), 13461349 (2015).


MF03 
Contributed Talk 
15 min 
02:22 PM  02:37 PM 
P1703: AN EFFECTIVEHAMILTONIAN APPROACH TO CH_{5}^{+}, USING IDEAS FROM ATOMIC SPECTROSCOPY 
JON T. HOUGEN, Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD, USA; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF03 
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In this talk we present the first steps in the design of an effective Hamiltonian for the vibrationrotation energy levels of CH_{5}^{+}. Such a Hamiltonian would allow calculation of energy level patterns anywhere along the path travelled by a hypothetical CH_{5}^{+} (or CD_{5}^{+}) molecule as it passes through various coupling cases, and might thus provide some hints for assigning the observed highresolution spectra. The steps discussed here, which have not yet addressed computational problems, focus on mapping the vibrationrotation problem in CH_{5}^{+} onto the fiveelectron problem in the boron atom, using ideas and mathematical machinery from Condon and Shortley’s book on atomic spectroscopy. The mapping ideas are divided into: (i) a mapping of particles, (ii) a mapping of coordinates (i.e., mathematical degrees of freedom), and (iii) a mapping of quantum mechanical interaction terms. The various coupling cases along the path correspond conceptually to: (i) the analog of a freerotor limit, where the H atoms see the central C atom but do not see each other, (ii) the lowbarrier and highbarrier tunneling regimes, and (iii) the rigidmolecule limit, where the H atoms remain locked in some fixed molecular geometry. Since the mappings considered here often involve significant changes in mathematics, a number of interesting qualitative changes occur in the basic ideas when passing from B to CH_{5}^{+}, particularly in discussions of: (i) antisymmetrization and symmetrization ideas, (ii) n,l,m_{l},m_{s} or n,l,j,m_{j} quantum numbers, and (iii) RussellSaunders computations and energy level patterns. Some of the mappings from B to CH_{5}^{+} to be discussed are as follows. Particles: the atomic nucleus is replaced by the C atom, the electrons are replaced by protons, and the empty space between particles is replaced by an “electron soup.” Coordinates: the radial coordinates of the electrons map onto the five local CH stretching modes, the angular coordinates of the electrons map onto three rotational degrees of freedom and seven bending vibrational degrees of freedom. The halfintegral electron spins map onto halfintegral proton spins or onto integral deuterium spins (for CD_{5}^{+}). Interactions: the Coulomb attraction between nucleus and electrons maps onto a Morseoscillator CH stretching potential, spinorbit interaction maps onto protonspinoverallrotation interaction, and Coulomb repulsion between electrons maps onto some kind of proton repulsion that leads to the equilibrium geometry.


MF04 
Contributed Talk 
15 min 
02:39 PM  02:54 PM 
P1573: IMPACT OF ENERGETICALLY ACCESSIBLE PROTON PERMUTATIONS IN THE SPECTROSCOPY AND DYNAMICS OF H_{5}^{+} 
ZHOU LIN, Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA; ANNE B McCOY, Department of Chemistry, University of Washington, Seattle, WA, USA; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF04 
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H _{5}^{+} has been proposed to be the intermediate of the astrochemically interesting proton transfer reaction H _{3}^{+} + H _{2} → H _{2} + H _{3}^{+}.
The scrambling of five protons in this floppy, "structureless" ion introduces complications to its highresolution rovibrational spectroscopy and the proton transfer dynamics between H _{3}^{+} and H _{2}.
Quantum chemical studies are performed to predict and interpret the spectroscopic and dynamical properties of H _{5}^{+}, with special consideration paid to the group theoretical aspects.
If the full permutation of protons were allowed in H _{5}^{+}, just like in CH _{5}^{+}, the system should have been characterized by the G _{240} complete permutationinversion group.
X.G. Wang
and T. Carrington Jr., J. Chem. Phys., 129, 234102 (2008).
However, our diffusion Monte Carlo calculations indicate that such a full permutation is not allowed for most of the molecular configurations sampled by the reaction path of the proton transfer process in question,
and the energetically accessible permutations are functions of the distance between the H _{3}^{+} and H _{2} fragments. Z. Lin and A. B. McCoy, J. Phys. Chem. A, 119, 12109 (2015).In the present study, we investigate two extreme geometries of H _{5}^{+}, the [H _{2}HH _{2}] ^{+} sharedproton intermediate and the H _{3}^{+}… H _{2} longrange complex, using two subgroups of
G _{240}, G _{16} and G _{24}, respectively.
In these two limiting circumstances, we derive the symmetryadapted basis functions for the energy levels that describe the nuclear spins and the rovibrational motions of H _{5}^{+}.
Based on the results of these derivations, we discuss the spectroscopic properties of H _{5}^{+}, including the coupling between different rovibrational degrees of freedom in the effective nuclear
motion Hamiltonian, the electricdipole selection rules for rovibrational spectroscopy, and correlations of energy levels between [H _{2}HH _{2}] ^{+} and H _{3}^{+}… H _{2}.
Our study can be considered as the first step towards the implementation of future quantitative theoretical investigations for comparison with spectroscopic and dynamical experiments.
Z. Lin, submitted to J. Mol. Spec.
Footnotes:
X.G. Wang
and T. Carrington Jr., J. Chem. Phys., 129, 234102 (2008).
Z. Lin and A. B. McCoy, J. Phys. Chem. A, 119, 12109 (2015).
Z. Lin, submitted to J. Mol. Spec.


MF05 
Contributed Talk 
15 min 
02:56 PM  03:11 PM 
P2127: VARIATION OF CH STRETCH FREQUENCIES WITH CH_{4} ORIENTATION IN THE CH_{4} − F^{−} COMPLEX: MULTIPLE RESONANCES AS VIBRATIONAL CONICAL INTERSECTIONS 
BISHNU P. THAPALIYA, DAVID S. PERRY, Department of Chemistry, The University of Akron, Akron, OH, USA; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF05 
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In the CH_{4} − F^{−} complex, an adiabatic separation of the CH stretch frequencies from the CH_{4} orientational coordinates allows the calculation of the four adiabatic CH stretch surfaces. These ab initio calculations reveal (i) a large variation of CH stretch frequencies ( 100 cm^{−1}) in the orientational space and (ii) the existence of four symmetrically equivalent sets of vibrational conical intersections (CIs). Two sets of symmetryallowed CIs are identified in addition to the symmetryrequired CIs at the front and backside C_{3v} geometries. These results have implications for the evolution of excited CH vibrations in methane during its approach to a potentially reactive surface.


MF06 
Contributed Talk 
15 min 
03:13 PM  03:28 PM 
P1748: SADDLE POINT LOCALIZATION OF MOLECULAR WAVEFUNCTIONS 
GEORG CH. MELLAU, Physikalisch Chemisches Institut, Justus Liebig Universitat Giessen, Giessen, Germany; ALEKSANDRA A. KYUBERIS, Microwave Spectroscopy, Institute of Applied Physics, Nizhny Novgorod, Russia; OLEG L. POLYANSKY, Department of Physics and Astronomy, University College London, London, UK; NIKOLAY FEDOROVICH ZOBOV, Microwave Spectroscopy, Institute of Applied Physics, Nizhny Novgorod, Russia; ROBERT W FIELD, Department of Chemistry, MIT, Cambridge, MA, USA; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF06 
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The quantum mechanical description of isomerization is based on bound eigenstates of the molecular potential energy surface. For the nearminimum regions there is a textbookbased relationship between the potential and eigenenergies. Here we show how the saddle point region that connects the two minima is encoded in the energy levels and wave functions of the potential energy surface.





03:30 PM 
INTERMISSION 


MF07 
Contributed Talk 
15 min 
03:47 PM  04:02 PM 
P1674: SPECTROSCOPIC CHARACTERIZATION OF ISOMERIZATION TRANSITION STATES 
JOSHUA H BARABAN, Department of Chemistry, University of Colorado, Boulder, CO, USA; BRYAN CHANGALA, Department of Physics, JILA  University of Colorado, Boulder, CO, USA; GEORG CH. MELLAU, Physikalisch Chemisches Institut, Justus Liebig Universitat Giessen, Giessen, Germany; JOHN F. STANTON, Department of Chemistry, The University of Texas, Austin, TX, USA; ANTHONY MERER, Department of Chemistry, University of British Columbia, Vancouver, BC, Canada; ROBERT W FIELD, Department of Chemistry, MIT, Cambridge, MA, USA; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF07 
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Transition state theory is central to our understanding of chemical reaction dynamics. We demonstrate here a method for extracting transition state energies and properties from a characteristic pattern found in frequency domain spectra of isomerizing systems. This pattern, a dip in the spacings of certain barrierproximal vibrational levels, can be understood using the concept of effective frequency, ω^{eff}. The method is applied to the cistrans conformational change in the S_{1} state of C_{2}H_{2} and the bondbreaking HCNHNC isomerization. In both cases, the barrier heights derived from spectroscopic data agree extremely well with previous ab initio calculations. We also show that it is possible to distinguish between vibrational modes that are actively involved in the isomerization process and those that are passive bystanders. (This work has been published in J. H. Baraban, P. B. Changala, G. Ch. Mellau, J. F. Stanton, A. J. Merer, and R. W. Field. Spectroscopic characterization of isomerization transition states. Science, 350(6266):13381342, 2015.)


MF08 
Contributed Talk 
15 min 
04:04 PM  04:19 PM 
P1650: ELECTRON ANISOTROPY AS A SIGNATURE OF MODE SPECIFIC ISOMERIZATION IN VINYLIDENE [Research supported by the Australian Research
Council Discovery Project Grant DP160102585] 
STEPHEN T GIBSON, BENJAMIN A LAWS, Research School of Physics, Australian National University, Canberra, ACT, Australia; RICHARD MABBS, Department of Chemistry, Washington University, St. Louis, MO, USA; DANIEL NEUMARK, Department of Chemistry, The University of California, Berkeley, CA, USA; CARL LINEBERGER, Department of Chemistry and Biochemistry, JILA  University of Colorado, Boulder, CO, USA; ROBERT W FIELD, Department of Chemistry, MIT, Cambridge, MA, USA; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF08 
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r0pt
Figure
The nature of the isomerization process that turns vinylidene into acetylene has been awaiting advances in experimental methods, to better define fractionation widths beyond those available in the seminal 1989 photoelectron spectrum measurement. K. M. Ervin, J. Ho, and W. C. Lineberger, J. Chem. Phys. 91, 5974 (1989). doi:10.1063/1.457415his has proven a challenge. The technique of velocitymap imaging (VMI) is one avenue of approach. Images of electrons photodetached from vinylidene negativeions, at various wavelengths, 1064 nm shown, provide more detail, including unassigned structure, but only an incremental improvement in the instrument line width. Intriguingly, the VMIs demonstrate a mode dependent variation in the electron anisotropy. Most notable in the figure, the innerring transition clusters are discontinuously, more isotropic. Electron anisotropy may provide an alternative key to examine the character of vinylidene transitions, mediating the necessity for an extreme resolution measurement. Vibrational dependent anisotropy has previously been observed in diatomic photoelectron spectra, associated with the coupling of electronic and nuclear motions. M. van Duzor et al. J. Chem. Phys. 133, 174311 (2010). doi:10.1063/1.3493349html:<hr /><h3>Footnotes:
K. M. Ervin, J. Ho, and W. C. Lineberger, J. Chem. Phys. 91, 5974 (1989). doi:10.1063/1.457415T
M. van Duzor et al. J. Chem. Phys. 133, 174311 (2010). doi:10.1063/1.3493349


MF09 
Contributed Talk 
15 min 
04:21 PM  04:36 PM 
P2051: OBSERVING QUANTUM MONODROMY: AN ENERGYMOMENTUM MAP BUILT FROM EXPERIMENTALLYDETERMINED LEVEL ENERGIES OBTAINED FROM THE ν_{7} FARINFRARED BAND SYSTEM OF NCNCS 
DENNIS W. TOKARYK, STEPHEN CARY ROSS, Department of Physics, University of New Brunswick, Fredericton, NB, Canada; BRENDA P. WINNEWISSER, MANFRED WINNEWISSER, FRANK C. DE LUCIA, Department of Physics, The Ohio State University, Columbus, OH, USA; BRANT E. BILLINGHURST, EFD, Canadian Light Source Inc., Saskatoon, Saskatchewan, Canada; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF09 
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The concept of Quantum Monodromy (QM) provides a fresh insight into the structure of rovibrational levels in those flexible molecules for which a bending mode can carry the molecule through the linear configuration. To confirm the existence of QM in a molecule required the fruits of several strands of development: the formulation of the abstract mathematical concept of monodromy, including the exploration of its relevance to systems described by classical mechanics and its manifestation in quantum molecular applications; the development of the required spectroscopic technology and computeraided assignment; and the development of a theoretical model to apply in fitting to the observed data. We present a timeline for each of these strands, converging in our initial confirmation of QM in NCNCS from pure rotational data alone. B. P. Winnewisser et al., Phys. Rev. Lett. 95, 243002 (2005).n that work a Generalised SemiRigid Bender (GSRB) Hamiltonian was fitted to the experimental rotational structure. Rovibrational energies calculated from the fitted GSRB parameters allowed us to construct an "EnergyMomentum" map and confirm the presence of QM in NCNCS. In further experimental work at the Canadian Light Source Synchrotron we have identified a network of transitions directly connecting the relevant energy levels and thereby have produced a refined Energy Momentum map for NCNCS from experimental measurements alone. This map extends from the ground vibrational level to well above the potential energy barrier, beautifully illustrating the characteristic signature of QM in a system uncomplicated by interaction with other vibrational modes.
Footnotes:
B. P. Winnewisser et al., Phys. Rev. Lett. 95, 243002 (2005).I


MF10 
Contributed Talk 
15 min 
04:38 PM  04:53 PM 
P1797: SPECTROSCOPY OF H_{2}^{+} AND HD^{+} NEAR THE DISSOCIATION THRESHOLD: SHAPE AND FESHBACH RESONANCES 
MAXIMILIAN BEYER, FREDERIC MERKT, Laboratorium für Physikalische Chemie, ETH Zurich, Zurich, Switzerland; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF10 
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r0pt
Figure
We use high Rydberg states to measure the properties of H _{2}^{+} and HD ^{+} in the vicinity of their dissociation limits H ^{+}+H, H ^{+}+D and H+D ^{+}, with particular emphasis on quasibound rovibrational levels above the dissociation threshold of the X ^{+} ^{2}Σ _{g}^{+} ground state.
Although the existence of these quasibound levels has been predicted a long time ago, they have never been observed. Positions and widths of the lowest resonances have not been calculated either.
Given the role that such states play in the threebody and radiative recombination of H(1s) and H ^{+} to form H _{2}^{+}, this lack of data may be regarded as one of the largest unknown aspects of this otherwise accurately known fundamental molecular cation.
We present measurements of the positions and widths of the lowestlying quasibound rotational levels (shape resonances) of H _{2}^{+}, located close to the top of the centrifugal barriers and which decay by quantummechanical tunneling.
For HD ^{+} we present measurements of rovibrational levels of the A ^{+} ^{2}Σ _{u}^{+} state, located between the two dissociation limits. Because of the gusymmetry breaking in HD ^{+}, these levels are coupled to the H ^{+}+D continuum by nonadiabatic interactions (Feshbach resonances).
The experimental results will be compared with the positions and widths we calculate for these levels using a potential model for the X ^{+} and the A ^{+} state of H _{2}^{+} and HD ^{+} which includes adiabatic, nonadiabatic, relativistic and radiative corrections to the BornOppenheimer potential energies.


MF11 
Contributed Talk 
15 min 
04:55 PM  05:10 PM 
P1985: A DIATOMIC MOLECULE WITH EXTREMELY LARGE AMPLITUDE MOTION IN ITS VIBRATIONAL STATES THAT HAVE LENGTHS OF AT LEAST 12,000 ANGSTROMS. 
NIKESH S. DATTANI, Department of Chemistry, Kyoto University, Kyoto, Japan; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF11 
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The stateoftheart empirical potential, and the stateoftheart ab initio potential for the b(1 ^{3}Π _{2u}) state of ^{7,7}Li _{2} agree with each other that the (v=100,J=0) rovibrational state has an outer classical turning point larger than the diameter of most bacteria and many animal cells. The 2015 empirical potential Dattani (2015) http://arxiv.org/abs/1508.07184v1ased on a significant amount of spectroscopic data, predicts the (v=100,J=0) level to be bound by only 0.000 000 000 004 cm ^{−1} ( 0.2 Hz). The outer turning point of the vibrational wavefunction is about 671 000 Å or 0.07 mm. Here, the two Li atoms are bound to each other, despite being nearly as far apart as the lines on a macroscopic ruler. The 2014 ab initio calculation based on a powerful Fock space MRCC method Musial & Kucharski (2014) Journal of Chemical Theory and Computation, 10, 1200.nd with the longrange tail anchored by C _{3}^{7Li}/r ^{3} with the ultrahigh precision 2015 value of C _{3}^{7Li}, has this same level bound by 0.000 000 000 1 cm ^{−1} ( 3 Hz), with an outer turning point of > 0.01 mm. While this discovery occurred during a study of Li _{2}, the b(1 ^{3}Π _{2u}) states of heavier alkali diatomics are expected to have even larger amplitude vibrational states. While it might be tempting to call these very large molecules "Rydberg molecules", it is important to remember that this term is already used to describe highly excited electronic states whose energy levels follow a formula similar to that for the famous Rydberg series. The highly delocalized vibrational states are a truly unfamiliar phenomenon.
Footnotes:
Dattani (2015) http://arxiv.org/abs/1508.07184v1b
Musial & Kucharski (2014) Journal of Chemical Theory and Computation, 10, 1200.a


MF12 
Contributed Talk 
15 min 
05:12 PM  05:27 PM 
P1601: FIT POINTWISE AB INITIO CALCULATION POTENTIAL ENERGIES TO A MULTIDIMENSION MORSE/LONGRANGE MODEL 
YU ZHAI, HUI LI, Institute of Theoretical Chemistry, Jilin University, Changchun, China; ROBERT J. LE ROY, Department of Chemistry, University of Waterloo, Waterloo, ON, Canada; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF12 
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r0pt
Figure
A potential energy surface (PES) is a fundamental tool and source of understanding for theoretical spectroscopy and for dynamical simulations. Making correct assignments for highresolution rovibrational spectra of floppy polyatomic and van der Waals molecules often relies heavily on predictions generated from a high quality ab initio potential energy surface. Moreover, having an effective analytic model to represent such surfaces can be as important as the ab initio results themselves. For the onedimensional potentials of diatomic molecules, the most successful such model to date is arguably the "Morse/LongRange" (MLR) function developed by R. J. Le Roy and coworkers. Mol. Phys. 105, 663 (2007); J. Chem. Phys. 131, 204309 (2009); Mol. Phys. 109, 435 (2011).t is very flexible, is everywhere differentiable to all orders. It incorporates correct predicted longrange behaviour, extrapolates sensibly at both large and small distances, and two of its defining parameters are always the physically meaningful well depth D _{e} and equilibrium distance r _{e}.
Extensions of this model, called the MultiDimension Morse/LongRange (MDMLR) function,
have been applied successfully to atompluslinear molecule, linear moleculelinear molecule and atomnonlinear molecule systems. Phys. Chem. Chem. Phys. 10, 4128 (2008); J. Chem. Phys. 130, 144305 (2009); J. Chem. Phys. 132, 214309 (2010); J. Chem. Phys. 140, 214309 (2014); J. Chem. Phys. 144, 014301 (2016).owever, there are several technical challenges faced in modelling the interactions of general moleculemolecule systems, such as the absence of radial minima for some relative alignments, difficulties in fitting shortrange potential energies, and challenges in determining relativeorientation dependent longrange coefficients. This talk will illustrate some of these challenges and describe our ongoing work in addressing them.
Footnotes:
Mol. Phys. 105, 663 (2007); J. Chem. Phys. 131, 204309 (2009); Mol. Phys. 109, 435 (2011).I
Phys. Chem. Chem. Phys. 10, 4128 (2008); J. Chem. Phys. 130, 144305 (2009); J. Chem. Phys. 132, 214309 (2010); J. Chem. Phys. 140, 214309 (2014); J. Chem. Phys. 144, 014301 (2016).H


MF13 
Contributed Talk 
10 min 
05:29 PM  05:39 PM 
P2238: INFRARED AND MICROWAVE SPECTRA OF NeWATER COMPLEX 
XUNCHEN LIU, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China; JAVIX THOMAS, YUNJIE XU, Department of Chemistry, University of Alberta, Edmonton, AB, Canada; DAN HOU, HUI LI, Institute of Theoretical Chemistry, Jilin University, Changchun, China; 
IDEALS Archive (Abstract PDF / Presentation File) 
DOI: https://dx.doi.org/10.15278/isms.2016.MF13 
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The binary complex of rare gas atom and water is an ideal model to study the anisotropic potential energy surface of van der Waals interaction and the large amplitude motion. Although XeH_{2}O, KrH_{2}O, ArH_{2}O, ArD_{2}O and even NeD_{2}O complexes were studied by microwave or high resolution infrared spectroscopy, the lighter NeH_{2}O complex has remained unidentified.
In this talk, we will present the theoretical and experimental investigation of the NeH_{2}O complex. A fourdimension PES for H_{2}ONe which only depended on the intramolecular (Q2) normalmode coordinate of H2O monomer was calculated in this work to determine the rovibrational energy levels and midinfrared transitions.
Aided with the calculated transitions, we were able to assigned the high resolution midinfrared spectra of both ^{20}NeH_{2}O and ^{22}NeH_{2}O complexes that are generated with a pulsed supersonic molecular beam in a multipass direct absorption spectrometer equiped with an external cavity quantum cascade laser at 6 μm.
Several bands of both para and ortho NeH2O were assigned and fitted using the Hamiltonian with strong Coriolis and angularradical coupling terms.
The predicted groud state energy levels are then confirmed by the J=10 and J=21 transitions measurement using a cavity based Fourier transform microwave spectrometer.

