Quick Running Gaussian Start 11.Edit the new input file. Notice that NewZMat has set up a Hartree-Fock calculation by default,using the 6-31G(d)basis set.The molecule specification in the generated file is also in Z-matrix format rather than Cartesian coordinates.You can now edit this file to modify the procedure,basis set,and type of run desired.We won't bother running this file,since it is the same job as the one we just completed. Batch Processing Although we ran the water calculation interactively,we recommend batch processing for Gaussian jobs on multiuser systems where a batch facility is available.On some systems,such as those at supercomputer centers,only batch processing is allowed. VMS users may execute water.com as a batch job using the Submit command.On UNIX systems supporting the NQS batch facility,the subg94 command provided with Gaussian 94 may be used.Here is an example: subg94 queue-name h2o.com where quewe-name is the name of the desired batch queue.The output from the job will automatically go to the file water.log.Alternatively,on UNIX systems,Gaussian jobs may be run in the background at lowered priority by initiating them with the nice command: $nice g94 <h2o.com >h2o.log& This concludes the UNIX and VMS-specific portion of the tutorial.Turn to page xlix to continue learning about Gaussian,where we examine Gaussian output. Tutorial for Windows Systems This tutorial assumes that you have already installed Gaussian on your PC and that you know how to navigate within Windows and run programs from the Program Manager.These instructions assume that you are using Windows 3.1;Windows 95 users will need to adjust them for the changes introduced in that operating system. The following steps are necessary to run a Gaussian calculation: ◆Start the program. Load or enter Gaussian input. Exploring Chemistry with Electronic Structure Methods
Quick Start I Running Gaussian Tutorial for Windows Systems 11. Edit the new input file. Notice that NewZMat has set up a Hartree-Fock calculation by default, using the 6-31G(d) basis set. The molecule specification in the generated file is also in Z-matrix format rather than Cartesian coordinates. You can now edit this file to modify the procedure, basis set, and type of run desired. We won't bother running this file, since it is the same job as the one we just completed. Batch Processing Although we ran the water calculation interactively, we recommend batch processing for Gaussian jobs on multiuser systems where a batch facility is available. On some systems, such as those at supercomputer centers, only batch processing is allowed. VMS users may execute water.com as a batch job using the Submi t command. On UNIX systems supporting the NQS batch facility, the subg94 command provided with Gaussian 94 may be used. Here is an example: % aubg94 queue-name h20.com where queue-name is the name of the desired batch queue. The output from the job will automatically go to the file water.log. Alternatively, on UNIX systems, Gaussian jobs may be run in the background at lowered priority by initiating them with the nice command: % nice g94 <h20.com >h20.1og • This concludes the UNIX and VMS-specific portion of the tutorial. Turn to page xlix to continue learning about Gaussian, where we examine Gaussian output. I r I ! This tutorial assumes that you have already installed Gaussian on your PC and that you know how to navigate within Windows and run programs from the Program i Manager. These instructions assume that you are using Windows 3.1; Windows 95 ! users will need to adjust them for the changes introduced in that operating system. The following steps are necessary to run a Gaussian calculation: + Start the program. + Load or enter Gaussian input. xxxviii Exploring Chemistry with Electronic Structure Methods t ____l
Tutorial for Windows Systems ◆ Start execution of the job. ◆ Examine and interpret the output. 1.Start the program by double clicking on the Gaussian 94W icon. This icon is usually located in the G94W program group.If you moved this icon to a different program group,select it from the appropriate location. Gaussian 94W The main program window is now open. 2.Locate each of the labeled items in the illustration below in the window on your screen. Output filename Editing icons .1,,i11127 Menu bar- Elle Process Utlliles Mew Help Job control icons- D即T同厂四可 Input filename Job progress display CG94WL311.cxc Is proccsslng... Standard orientation: Center Atonic Coordinates (Angstroms) Muaber Huaber P Gaussian 94 oulput area 0,000000 1,289000 0.000000 2 6 1.116307 -0.644500 0.000000 3 6 -1.116307 -0.644500 0.000000 4 6 0.000000 0.000000 0,772000 6 0.000000 0.000000 -0.772000 1 0.905466 1,870299 0.000000 1 -0.905466 1,870299 0,000000 8 1 1.166993 -1.719306 0.000000 11 2.072459 -0.150993 0.000000 -2.072459 -0.150993 0.000000 11 1 -1.166993 -1,719306 0.000000 Stotus ine We'll examine each of these items in turn. Exploring Chemistry with Electronic Structure Methods xxxix
Tutorial for Windows Systems • Start execution ofthe job. • Examine and interpret the output. 1. Start the program by double clicking on the Gauuian 94W icon. Gaussian 94W This icon is usually located in the G94W program group. Ifyou moved this icon to a different program group, select it from the appropriate location. The main program window is now open. 2. Locate each of the lab.led items in the illustration below in the window on your screen. 0.000000 0.000000 0.000000 0.772000 -0.772000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 1.289000 -0.644500 -0.644500 0.000000 0.000000 1.870299 1. 870299 -1. 719306 -0.150993 -0.150993 -1. 719306 CoordInates (Anqscroa5) X y Z 0.000000 1.116307 -1.116307 0.000000 0.000000 0.905466 -0.905466 1.166993 2.072459 -2.072459 -1.166993 Standard orIentatIon: Ato.le JruIIbe%: 1 2 3 4 5 6 7 8 9 10 11 Cente%: JruIIbe%: Slatus ~ne--- Menu bar---+ Job control icont---____ Input filenam.--- Job progress displftv--- GallSSion 94 output area-----IWe'll examine each ofthese items in turn. Exploring Chemistry with Electronic Structure Methods xxxix
Quick Running Gaussian Start Before you can run a Gaussian job,you must provide the program with the input it needs.The File menu is used to create a new input file or to modify an existing one. Create a new input file and open the Job Entry window. Fe Process 业tiliti New Open... Load existing Gaussian input file or convert a Modify... molecular structure. Designate preferred Preferences default settings. Edit the currently loaded input file. Exit Alt+F4- Exit from Goussian 94w. 3. Select New from the File menu to create a new Gaussian input file. The Job Entry window now appears.This diagram indicates the major input sections: ol I utry Flle Edh CheckFoute SetStart Specifies theoretical model type of job Brief description of job Charge spin multiplicity Molecular structure We'll fill in this window with the input for an energy calculation on water. This window is divided into several separate individually scrollable sections,each of which will hold a different part of the Gaussian input.The cursor is initially placed in the%Section section.You move the cursor to the next section by pressing the Tab key, Exploring Chemistry with Electronic Structure Methods
3. Select New from the File menu to create a new~aussian input file. Designate preferred --+---- defauh settings. E~it AIt+F~ --+---- Exit from GausMan 94W Preferences Before you can run a Gaussian job, you must provide the program with the input it neecl~. The File menu is used to create a new input file or to modify an existing one. Create a new input file and open the Job Entry window. load existing Gaussian input file or convert a molecular structure. Edit the currently loaded input file. Quick Running Gaussian Start The Job Entry window now appears. This diagram indicates the major input sections: Specifies theoretical model &type of job Brief description of job Charge & spin multiplicity Molecular structure ----f'ifWe'll fill in this window with the input for an energy calculation on water. This window is divided into several separate individually scrollable sections, each of which will hold a different part ofthe Gaussian input. The cursor is initiaUy placed in the % Section section. You move the cursor to the next section by pressing the Tab key; xl Exploring Chemistry with Electronic Structure Methods
Tutorial for Windows Systems Shift Tab moves the cursor to the previous section.Or,you can move directly to any section by clicking in it with the mouse. 4.Move the cursor to the second section of the window,which is labeled Route Section. This section is used to enter the route section of the job,which contains instructions for running the calculation. 5. Type the following line into the window: #TRHF/6-31G(d)Test The route section specifies the procedure and basis set we want to use for this calculation: Keyword Meaning RHF Restricted Hartree-Fock(restricted means that there are no unpaired electrons in our molecule) 6-31Gd Use the 6-31G(d)basis set (which is a useful and often-recommended basis set). We've chosen a restricted(R)Hartree-Fock(HF)calculation using the 6-31G(d)basis set(6-31Gld)). Lines in the route section begin with a sign.#T requests terse output from the program (only the essential results),#alone requests normal(traditional)Gaussian output,and #P requests the maximum amount of detail in the output file. All route sections must include a procedure keyword and a basis set keyword. Additional keywords further specify the type of calculation desired and additional options. We've also included only one additional keyword,Test,which.says this is a test calculation whose results should not be archived in the Gaussian archive (although archiving is not available for Gaussian 94W). 6.Move the cursor to the third section of the window,labelled Title section. The title section of a Gaussian input file contains a brief(usually one-line)description of the job.Enter something like the following into this section: My first Gaussian job:water single point energy Exploring Chemistry with Electronic Structure Methods x
Tutorial for Windows Systems Shift Tab moves the cursor to the previous section. Or, you can move directly to any section by clicking in it with the mouse. . 4. Move the cursor to the second section of the windoYl, which is labeled Route Section. This section is used to enter the route section of the job, which contains instructions for running the calculation. 5. Type the following line into the window: #T RHF/6-31Gld) Test The route section specifies the procedure and basis set we want to use for this calculation: Keyword RHF 6-31Gldl Meaning Restricted Hartree-Fock (restricted means that there are no unpaired electrons in our molecule) Use the 6-31G(d) basis set (which is a useful and often-reconunended basis set). We've chosen a restricted (R) Hartree-Fock (HF) calculation using the 6-31G(d) basis set (6-31Gld». Lines in the route section begin with a # sign. #T requests terse output from the program (only the essential results), # alone requests normal (traditional) Gaussian output, and #P requests the maximum amount of detail in the output me. All route sections must include a procedure keyword and a basis set keyword. Additional keywords further specify the type of calculation desired and additional options. We've also included only one additional keyword, Test, which. says this is a test calculation whose results should not be archived in the Gaussian archive (although archiving is not available for Gaussian 94W). 6. Move the cursor to the third section of the window, labelled Title section. The title section of a Gaussian input file contains a brief (usually one-line) description ofthe job. Enter something like the following into this section: My first Gaussian job: water single point energy Exploring Chemistry with Electronic Structure Methods xli
Quick Running Gaussian Start The title section appears in the output and is stored in the Gaussian archive entry but is not otherwise used by the program. 7.Move the cursor to the next section of the window,labelled Charge Multipl. This section and the one following it(Molecule Specification)specify the structure of the molecule system to be investigated.This section holds the charge on the molecule and its spin multiplicity.Each of them is entered as an integer on this line,with one or more spaces separating them. Since water is a neutral molecule,its charge is 0.Spin multiplicity refers to the arrangement of the electrons within the molecule.Water has no unpaired electrons, so it is a singlet and its spin multiplicity is 1(Spin multiplicity is discussed in Chapter 2,and molecule specifications in general are discussed in Appendix B). 8. Enter the following values into the Charge and Multiplicity section: 01 The Molecule Specification section holds the type and positions of each of the atoms in the molecule.For this job,we'll enter our water molecule's structure in Cartesian coordinates. 9. Enter the following data into the Molecule Specification section: 0-0.4640.1770.0 H-0,4641.1370.0 H0.441-0.1430.0 This completes the input needed for this job.The completed screen should look similar to the one illustrated on the next page.We will save this input to a file for future reference and then run the job. 10.Select Save File from the File menu. This directs the program to save the input you typed in to a file.Select the desired directory location in the standard Windows save dialog box,and give the input file the name H2O.GJF.GJF is the extension used for Gaussian input files on Windows systems (standing for Gaussian Job File). xlii Exploring Chemistry with Electronic Structure Methods
7. Move the cursor to the next section of the window, labelled Charge & Multipl. Quick Start I Running Gaussian The title section appears in the output and is stored in the Gaussian archive entry but is not otherwise used by the program. This section and the one following it (Molecule Specification) specify the structure of the molecule system to be investigated. This section holds the charge on the molecule and its spin multiplicity. Each ofthem is entered as an integer on this line, with one or more spaces separating them. Since water is a neutral molecule, its charge is O. Spin multiplicity refers to the arrangement of the electrons within the molecule. Water has no unpaired electrons, so it is a singlet and its spin multiplicity is 1 (Spin multiplicity is discussed in Chapter 2, and molecule specifications in general are discussed in Appendix B). 8. Enter the following values into the Charge and Multiplicity section: The Molecule Specification section holds the type and positions of each ofthe atoms in the molecule. For this job, we'll enter our water molecule's structure in Cartesian coordinates. 9. Enter the following data into the Molecule Specification section: o ~0.464 H -0.464 H 0.441 0.177 1.137 -0.143 0.0 0.0 0.0 This completes the input needed for this job. The completed screen should look similar to the one illustrated on the next page. We will save this input to a file for future reference and then run the job. 10. Seled Save File from the File menu. This directs the program to save the input you typed in to a file. Select the desirtd directory location in the standard Windows save dialog box~ and give the input file the name H20.GJF. GJF is the extension used for Gaussian input files on Windows systems (standing for Gaussian Job File). 1 xlii Exploring Chemistry with Electronic Structure Methods