Gaussian 03 Online Manual
Last update: 2 October 2006


These method keywords request two variations of the W1 method of Martin [94,95]. The first, selected with the W1U keyword, is the W1U method. This is the W1 method modified to use UCCSD instead of ROCCSD for open shell systems. W1BD requests a related method which substitutes BD for coupled cluster [96]. This method is both more expensive and more accurate than CBS-QB3 and G3.

You should specify alternative isotopes for W1 jobs using the standard method. However, the ReadIsotopes option is retained for rerunning completed calculations under different conditions.

Specify alternate temperature, pressure, and/or isotopes (the defaults are 298.15 K, 1 atmosphere, and the most abundant isotopes). This information appears in a separate input section having the format:

temp pressure [scale]                                                Must be real numbers.       
isotope mass for atom 1       
isotope mass for atom 2      	
isotope mass for atom n 

where temp, pressure, and scale are the desired temperature, pressure, and an optional scale factor for frequency data when used for thermochemical analysis (the default value defined by the specified method is used if scale is omitted or set to 0.0); these values must be real numbers. The remaining lines hold the isotope masses for the various atoms in the molecule, arranged in the same order as they appeared in the molecule specification section. If integers are used to specify the atomic masses, the program will automatically use the corresponding actual exact mass (e.g., 18 specifies O18, and Gaussian uses the value 17.99916).

Restart an incomplete W1 calculation.

Calculation Summary Output. After all of the output for the component job steps, Gaussian prints a table of results for these methods. Here is the key part of the output from a W1U calculation:

W1   Electronic Energy       -76.483031
Temperature=     298.150000   Pressure= 1.000000 
E(ZPE)=            0.020965   E(Thermal)= 0.023800 
W1 (0 K)=        -76.462067   W1   Energy= -76.459231 
W1 Enthalpy=     -76.458287   W1   Free Energy= -76.479709 

The predicted energy is given followed by values for the thermochemistry analysis.