Intermolecular potential energy surfaces

Jeziorski B, Moszynski R and Szalewicz K 1994 Perturbation theory approach to intermolecular potential energy surfaces of van der Waals complexes Chem. Rev. 94 1887... 

Nesbitt, D.J., Child, M.S., and Clary, D.C. (1989). Rydberg-Klein-Rees inversion of high resolution van der Waals infrared spectra An intermolecular potential energy surface for Ar+HF(t = 1), J. Chem. Phys. 90, 4855-4864. 

Hutson JM, Howard BJ (1981) The intermolecular potential energy surface of Ar-HCl. Mol Phys 43 493-516... 

Schmuttenmaer CA, Cohen RC, Saykally RJ (1994) Spectroscopic determination of the intermolecular potential energy surface for A r Nil,. J Chem Phys 101 146—173... 

Williams HL, Szalewicz K, Jeziorski B, Moszynski R, Rybak S (1993) Symmetry-adapted perturbation theory calculation of the Ar-H2 intermolecular potential energy surface. J Chem Phys 98 1279-1292... 

Elrod, M. J., and Saykally, R. J., Determination of the intermolecular potential energy surface for (HClj from vibration-rotation-tunneling spectra, J. Chem. Phys. 103,933-949 (1995). Latajka, Z., and Scheiner, S., Structure, energetics and vibrational spectra ofH-bonded systems. Dimers and trimers ofHFand HCl, Chem. Phys. 122, 413 30 (1988). 

B. Jeziorski, R. Moszynski, and K. Szalewicz, Chem. Rev., 94, 1887 (1994). Perturbation Theory Approach to Intermolecular Potential Energy Surfaces of van der Waals Complexes. 

Calculation of Intermolecular Potential Energy Surfaces Using Modified Molecular Mechanics Techniques. ... 

Weakly bound complexes display unusual structural and dynamical properties resulting from the shape of their intermolecular potential energy surfaces. They show large amplitude internal motions, and do not conform to the dynamics and selection rules based on the harmonic oscillator/rigid rotor models (4). Consequently, conventional models used in the analysis of the spectroscopic data fail, and the knowledge of the full intermolecular potential and dipole/polarizability surfaces is essential to determine the assignments of the observed transitions. 

Despite the clarity contained within the AM formalism, current collision theories such as the CC method, briefly outlined above, or the numerous modifications of reduced rigour, insight into the relationship between initial conditions and the outcomes is often very hard to obtain. Calculations are highly computer intensive, since many (j) channels must be summed over as the system traverses an intermolecular potential energy surface (PES). Furthermore, the PES must be accurately known for each collision pair. Scattering amplitudes are obtained but their relation to distinctive characteristics of the colliding species is rarely apparent and causal relationships are difficult to discern. Furthermore, any change in the collision partners, however small, requires a new PES appropriate to that pair, with... 

A. E. Barton and B. J. Howard, Faraday Discuss. Chem. Soc., 73,45 (1982). An Intermolecular Potential-Energy Surface for Hydrogen Fluoride Dimer. 

The complete intermolecular potential energy surface depends upon the intermolecular distance and up to five angles, as discussed in section Al.5,1.3. 

In addition to the dependence of the intermolecular potential energy surface on monomer vibrational level, the red-shifting of the monomer absorption as a function of the number of rare gas atoms in the cluster has been studied. The band origin for the Vj p =1- 0 vibration in a series of clusters Ar -HF, with 0 < < 5, was measured and compared to the HF vibrational frequency in an Ar matrix ( = oo). The monomer vibrational frequency Vjjp red shifts monotonically, but highly nonlinearly, towards the matrix value as sequential Ar atoms are added. Indeed, roughly 50% of the shift is already accounted for by = 3. 

Figure Cl.3.2. Coordinate systems used for intermolecular potential energy surfaces. (Taken from [60].)...

The terms within the parentheses are simply probabilities. The first term is the probability of finding the CSP in a given conformational state, the second term is the probability that the analyte is in a particular conformation and the last term is the probability that the two molecules are positioned and oriented in a particular way with respect to each other. Note that because the authors locate all the minima on the complex s intermolecular potential energy surfaces they can derive the entropy of the system as well. Therefore E is actually a good representation of the macroscopic free energy of interaction, which in this case corresponds to a Gibbs free energy. 

First those authors considered the binding site on the CSP. This is simply where the analytes spend most of their time around the CSP. The main question was do both analytes bind to the same place on the CSP or to different places A priori there is no way of knowing this, but by examining the intermolecular potential energy surfaces they were able to conclude, for the analytes studied, that the binding sites are the same for both enantiomers indicating that it is not where the analyte binds that is important but rather how it binds that is important. 

Intemiolecular energy evaluation (H-bonding, electrostatic and van der Waals interactions) for a regular distribution of points on the selector and selectand surface (According to the Lipkowitz procedure), INTERMOLECULAR POTENTIAL ENERGY SURFACE... 

Heltmann R, Bich E, Vogel E (2008) Ab initio intermolecular potential energy surface and second pressure virial coefficients of methane. J Chem Phys 128 214303... 

---