BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Noncovalently bound molecular dimers with more than four atoms: In
 ter- and intramolecular rovibrational states and frequency shifts from ful
 l-dimensional and fully coupled quantum calculations - Professor Zlatko Ba
 čić\, New York University
DTSTART:20210526T133000Z
DTEND:20210526T143000Z
UID:TALK132142@talks.cam.ac.uk
CONTACT:Lisa Masters
DESCRIPTION:Fluxional molecular dimers bound by noncovalent interactions h
 ave been the subject of intense research activity by experimentalists and 
 theorists alike for decades. Scientists have been drawn to these systems t
 o gain quantitative understanding of their vibration-rotation-tunneling dy
 namics dominated by strong nuclear quantum effects\, and account for them 
 in terms of accurate multidimensional potential energy surfaces. Crucial f
 or achieving these goals is the ability to compute rigorously\, as fully c
 oupled and full-dimensional\, the (ro)vibrational levels of floppy molecul
 ar dimers.  For complexes having four or five atoms\, such calculations in
  full dimensionality\, 6D and 9D\, respectively\, are very demanding alrea
 dy when the monomers are in their ground intramolecular vibrational states
 . The difficulty of the task increases sharply when the calculations are e
 xtended to excited intramolecular vibrational states. Because of the order
 -of-magnitude disparity between their frequencies and those of the intermo
 lecular vibrational modes\, typical for noncovalently bound molecular dime
 rs\, hundreds of highly excited intermolecular vibrational states have ene
 rgies below those of the monomer intramolecular vibrational excitations co
 nsidered. For a long time\, the prevailing view was that all of them have 
 to be converged if accurate excited intramolecular vibrational eigenstates
  are desired\, making the calculations prohibitively costly. This is the m
 ain reason why prior to our recent methodological developments that I will
  discuss in this talk\, there was not a single full-dimensional and fully 
 coupled quantum bound-state calculation in the literature involving weakly
  bound molecular dimers with more than four atoms that yielded converged e
 nergies of all intramolecular vibrational fundamentals\, together with exc
 ited intermolecular vibrational states. The turning point came when we rea
 lized [1\,2] that such calculations can be accomplished by including in th
 e final basis only a small number of low-lying intermolecular eigenstates 
 with energies far below those of the intramolecular vibrational eigenstate
 s\, drastically reducing the dimensionality of the problem. I will describ
 e the newly developed computational approach particularly well suited to t
 ake advantage of this insight [2\,3]\, and demonstrate its effectiveness b
 y reviewing our full-dimensional (9D) and fully coupled quantum bound-stat
 e calculations of H2O/D2O-CO [3]\, HDO--CO [4]\, and HCl-H2O [5] dimers. I
 n all instances\, intramolecular (ro)vibrational excitations of the monome
 rs and their frequency shifts are computed\, together with the low-energy 
 intermolecular (ro)vibrational states of the dimers within intramolecular 
 vibrational manifold. Finally\, if time permits\, I will touch upon our 9D
  quantum calculations of the inter- and intramolecular vibrational states 
 of benzene-H2O/HDO dimers\, for flexible water and rigid-benzene [6].\n\n\
 n\nReferences\n\n[1] D. Lauvergnat\, P. M. Felker\, Y. Scribano\, D. M. Be
 noit\, and Z. Bačić\, J. Chem. Phys.  150\, 154303 (2019).\n[2] P. M. Fe
 lker and Z. Bačić\, J. Chem. Phys. 151\, 024305 (2019).\n[3] P. M. Felke
 r and Z. Bačić\, J. Chem. Phys. 153\, 074107 (2020).\n[4] P. M. Felker a
 nd Z. Bačić\, J. Phys. Chem. A\, 125\, 980 (2021).\n[5] Y. Liu\, J. Li\,
  P. M. Felker and Z. Bačić\, Phys. Chem. Chem. Phys. 23\, 7101 (2021).\n
 [6] P. M. Felker and Z. Bačić\, J. Chem. Phys. 152\, 124103 (2020).
LOCATION:Zoom: Meeting ID: 977 2817 4648 Passcode: 343584
END:VEVENT
END:VCALENDAR