Study of the benzene⋅N2 intermolecular potential-energy surface

Abstract

The intermolecular potential-energy surface pertaining to the interaction between benzene and N 2 is investigated theoretically and experimentally. Accurate intermolecular interaction energies are evaluated for the benzene-N 2 van der Waals complex using the coupled cluster singles and doubles including connected triples ͓CCSD͑T͔͒ method and the aug-cc-pVDZ basis set extended with a set of 3s3p2d1 f 1g midbond functions. After fitting the energies to an analytic function, the intermolecular Schrödinger equation is solved to yield energies, rotational constants, and Raman-scattering coefficients for the lowest intermolecular levels of several benzene-N 2 isotopomers. Experimentally, intermolecular Raman spectra of jet-cooled h 6 -and d 6 -benzene-N 2 measured at 0.03 cm Ϫ1 resolution by mass-selective, ionization-detected stimulated Raman spectroscopies are reported. Seven intermolecular bands are assigned for each isotopomer, including transitions involving intermolecular bending and stretching vibrations and internal rotation about the benzene C 6 axis. These Raman data, together with measured rotational constants and binding energies obtained by other groups on benzene-N 2 , agree well with the theoretical results. Such agreement points to the promise of the quantum chemical methodology employed herein in future investigations of larger van der Waals complexes.

Chemical Dynamics Simulation of Low Energy N2 Collisions with Graphite

“…For the current study MP2/6-311++G­(d,p) theory was used and it gives a benzene + N 2 global minimum in which N 2 is parallel to the benzene plane and has a benzene + N 2 center-of-mass separation of 3.46 Å and a potential energy of −1.30 kcal/mol. These properties are in excellent agreement with experiment − and higher level theoretical values. − This structure is identified as orientation 1. Another structure was found, orientation 4, in which the internuclear axis of N 2 coincides with the C 6 axis of benzene.…”

Computational and experimental investigation of intermolecular states and forces in the benzene–helium van der Waals complex

“…To calculate Raman scattering coefficients we make the assumption that intermolecular Raman bands gain their intensity via the ''libration-induced mechanism,'' 29,46,50,54,55 wherein cluster polarizability components are modulated during the course of an intermolecular vibration by virtue of the changing projection of the permanent polarizability components of monomer moieties along cluster-fixed axes. With this approximation and Eq.…”

vdW‐TSSCDS—An automated and global procedure for the computation of stationary points on intermolecular potential energy surfaces

“…For Bz‐N 2 , which is a 5D problem in the rigid monomer approach and a 6D problem in our semirigid approach, Jaeger et al reported on minima, but not on TSs, on the IPES obtained at MP2/aug‐cc‐pVTZ level of theory. Lee et al determined an analytic function for the IPES on the CCSD(T)/aug‐cc‐pVDZ level including midbond functions in the basis set. For Bz‐H 2 O, that is 6D for the rigid monomer approach and 9D in our semirigid approach, previous studies include the work by Popelier et al, who found one minimum and two TSs using a Lennard‐Jones distributed multipole analysis potential.…”

“…These can be divided into two categories. Methods that rely on a fit which uses a grid of nonstationary points in a physically meaningful range of intermolecular coordinates also exist in an automatic fashion. Alternatively, other approaches make use of genetic or evolutionary algorithms in combination with a large variety of different methodologies allowing for the determination of minimum energy structures of molecular clusters .…”