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CBC216 Expt 1 (Gaussian) Please use the computers at the first 3 rows. CBC216 Expt 1 (Gaussian). Please do your pre-lab questions. You will not be able to proceed with the experiment if you have not read through the manual, and done your pre-lab.
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CBC216 Expt 1 (Gaussian)Please use the computersat the first 3 rows
CBC216 Expt 1 (Gaussian) • Please do your pre-lab questions. • You will not be able to proceed with the experiment if you have not read through the manual, and done your pre-lab. • You need to find out the bond angle and bond length of the H2O molecule • Google and Wikipedia are useful tools
Corrections to lab manual • Page 9 • xemacs template.inp & • g03 < XXX_go.inp > XXX_go.out & • Page 10 • C6H6_fq.inp (not C6H6_fq_inp)
Workflow of Expt 1 • Use Gaussian to find optimum geometry of H2O molecule • template_go.inp • Use optimum values from (1) to calculate vibrational frequencies of H2O, D2O, HDO • template_fq.inp • Find vibrational frequencies of Benzene • C6H6_fq.inp
Example of a Gaussian Input file %mem=64Mw %chk=H2O.chk #P B3LYP/6-31++G** Opt=tight test 0 1 O 0.0 0.0 0.0 H(Iso=1) 1.0 0.0 0.0 H(Iso=1) 0.0 1.0 0.0
CBC216 Expt 1 (Gaussian) • Points to note: • Ensure you key in the input file correctly • Blank spaces and blank lines ARE important • There must be at least 1 blank line at the end of the file. • Do not confuse ‘0’ (zero) with ‘O’ (big letter O); or ‘1’ (one) with ‘l’ (small letter l) • Integers and floating point numbers are differentie. ‘1’ is not equal to ‘1.0’
Modified Gaussian Input file %mem=64Mw %chk=H2O.chk #P B3LYP/6-31++G** Opt=tight test 0 1 O 0.0 0.0 0.0 H(Iso=1) 1.0 0.0 0.0 H(Iso=1) -1.0 0.0 0.0
CBC216 Expt 1 (Gaussian) • Some useful linux commands • ls : lists out the files you have in your directory • jobs : what jobs are currently running • & : execute a job in the background • ctrl-Z : stops a running job • bg : sends a stopped job to run in the background
Logging on to the PC • The power switch is behind the monitor; on the right side. Username: user Password: user
Logging into Linux • PuTTY XLaunch • Login as: cbc216gp# • Password: cbc216gp#
Workflow of Expt 1 • Use Gaussian to find optimum geometry of H2O molecule • template_go.inp --> save file as H2O_go.inp after changing coordinates • Use optimum values from (1) to calculate vibrational frequencies of H2O, D2O, HDO • template_fq.inp --> save file as H2O_fq.inp, D2O_fq.inp, HDO_fq.inp after changing coordinates and isotope number • Run Gaussian for all 3 water files and 1 benzene file concurrently: g03 < H2O_fq.inp > H2O_fq.out & g03 < D2O_fq.inp > D2O_fq.out & g03 < HDO_fq.inp > HDO_fq.out & g03 < C6H6_fq.inp > C6H6_fq.out &