IRC,

Lakestani, F., Validation of mathematical models of the ultrasonic inspection of steel components, PISC III report 6, IRC Inst. Adv. Mater., Petten, 1992. 

The Internet provides numerous powerful communication and multi-media tools, such as Inter Relay Chat (IRC), NetMeeting, White boards, Internet Phone, Archie, FTP, Telnet and many companies offer custom solutions with "plug-ins" But those are not the most important tools for access to information. The following outlines some of the "basics"... 

Here are just a few examples [5 - 18] of some good sites NTIAC, BlnstNDT, CSNDT, DGZfP, IOWA, SWRI, BAM, FhG, NASA, CORDIS, IRC, Panametrics, Krautkramer, IRT, QNet. 

Techniques have been developed within the CASSCF method to characterize the critical points on the excited-state PES. Analytic first and second derivatives mean that minima and saddle points can be located using traditional energy optimization procedures. More importantly, intersections can also be located using constrained minimization [42,43]. Of particular interest for the mechanism of a reaction is the minimum energy path (MEP), defined as the line followed by a classical particle with zero kinetic energy [44-46]. Such paths can be calculated using intrinsic reaction coordinate (IRC) techniques... 

A transition structure is, of course, a maximum on the reaction pathway. One well-defined reaction path is the least energy or intrinsic reaction path (IRC). Quasi-Newton methods oscillate around the IRC path from one iteration to the next. Several researchers have proposed methods for obtaining the IRC path from the quasi-Newton optimization based on this observation. 

The MEP is defined as the path of steepest descent in mass-weighted Cartesian coordinates. This is also called intrinsic reaction coordinate (IRC). In reality, we know that many other paths close to the IRC path would also lead to a reaction and the percentage of the time each path is taken could be described by the Boltzmann distribution. 

The reaction coordinate is calculated in a number of steps. If too few steps are used, then the points that are computed will follow the reaction coordinate less closely. Usually, the default number of points computed by software packages will give reasonable results. More points may be required for complex mechanisms. This algorithm is sometimes called the IRC algorithm, thus creating confusion over the definition of IRC. 

If the complete potential energy surface has already been computed, a reaction coordinate can be determined using an adaptation of the IRC algorithm. The IRC computation requires very little computer time, but obtaining the potential energy surface is far more computation-intensive than an ah initio IRC calculation. Thus, this is only done when the potential energy surface is being computed for another reason. 

If an entire potential energy surface has been computed, use an IRC algorithm with that surface. 

A number of types of calculations can be performed. These include optimization of geometry, transition structure optimization, frequency calculation, and IRC calculation. It is also possible to compute electronic excited states using the TDDFT method. Solvation effects can be included using the COSMO method. Electric fields and point charges may be included in the calculation. Relativistic density functional calculations can be run using the ZORA method or the Pauli Hamiltonian. The program authors recommend using the ZORA method. 

MEP (IRC, intrinsic reaction coordinate, minimum-energy path) the lowest-energy route from reactants to products in a chemical process MIM (molecules-in-molecules) a semiempirical method used for representing potential energy surfaces... 

Infrared absorption properties of 2-aminothiazole were reported with those of 52 other thiazoles (113). N-Deuterated 2-aminothiazole and 2-amino-4-methylthiazo e were submitted to intensive infrared investigations. All the assignments were performed using gas-phase studies of the shape of the vibration-rotation bands, dichroism, isotopic substitution, and separation of frequencies related to H-bonded and free species (115). With its ten atoms, this compound has 24 fundamental vibrations 18 for the skeleton and 6 for NHo. For the skeleton (Cj symmetry) 13 in-plane vibrations of A symmetry (2v(- h, 26c-h- Irc-N- and 7o)r .cieu.J and... 

Amberlite IRC-50 3.5 1.25 Methacrylic acid-DVB. Selectivity adsorbs organic gases such as antibiotics, alkaloids, peptides, and amino acids. Use pH >5. 

Golde, R.H., Lightning surges on overhead disiribuii(m lines caused by direct and indirect lightning strikes. AIEE Transactions (Power Apparatus and Systemi. 437-447. June (1959) IRC. 56-HV AC Circuit Breakers. 

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