Instructions for using Aces 2

A sample Aces 2 input file for H2O illustrating the use of a Z matrix to input the nuclear positions
Test run on water  <------------------- your comment (ignored by Aces 2) 
O                <------------------- Z matrix 
H 1 roh*         <------------------- Z matrix (* indicates optimization) 
H 1 roh* 2 ang*  <------------------- Z matrix (* indicates optimization) 
blank line 
roh=0.957          <------------------- initial value of roh 
ang=104.5          <------------------- initial value of ang 
blank line 
REFERENCE=RHF,SCF_EXPSTAR=1,DROPMO=1                              <---- job control parameters 
SPHERICAL=ON,MEM=10000000,SCF_CONV=12,SCF_MAXCYC=300,CC_CONV=9)   <---- job control parameters 

This input file corresponds to geometry optimization (*'s designate the parameters to be optimized), using the CCSD(T) method (CALCLEVEL=CCSD[T]) and the cc-PVDZ basis set (BASIS=CC-PVDZ). The lowest orbital is kept frozen (DROPMO=1) and the calculation utilizes the point symmetry of H2O (C2v). REFERENCE=RHF means that the restricted Hartree-Fock method is used to generate molecular orbitals. SPHERICAL=ON means that the spherical components of d, f, etc. orbitals (5d, 7f, etc.) are used. As you can see, you can control many things, including the SCF convergence, and the convergence criteria for solving the coupled-cluster equations. SCF_EXPSTAR=1 means that RPP (an algorithm for accelerating the convergence of the SCF process) is activated from iteration no. 1 (default: 15). The CCSD(T) calculation uses the analytic gradient capability of Aces 2 (unavailable in Gaussian 98 for higher-order methods, such as CCSD(T)).

And here is another input, corresponding to calculations of vertical excitation energies of CH+ with the EOMCCSD approach.

Test run on CH+       <------------------- your comment (ignored by Aces 2) 
C  0.0000000000  0.0000000000  0.0000000000 <------------------- Cartesian coordinates of the C nucleus 
H  0.0000000000  0.0000000000  2.1371300000 <------------------- Cartesian coordinates of the H nucleus 
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ESTATE_SYM=3/0/0/0,COORDINATE=CARTESIAN,CHARGE=1                       <---- job control parameters 
SPHERICAL=OFF,MEM=100000000,SCF_CONV=12,SCF_MAXCYC=300,CC_CONV=12)     <---- job control parameters 

As you can see, you can use Carterian coordinates instead of Z-matrix and bohr instead of Angstrom. ESTATE_SYM=3/0/0/0 means that you are interested in three excited states of the 1A1 symmetry (four numbers separated by "/" indicate numbers of calculated excited states in four symmetry blocks corresponding to irreducible representations of the C2v group). EXCITE=EOMEE indicates the calculation with the equation-of-motion coupled-cluster (EOMCC) approach for excited electronic states, CALC=CCSD means that the EOMCC calculation uses the CCSD approximation. CHARGE=1 means that the molecule is a cation. The reference configuration is RHF, since CH+ is a closed-shell system and the default for such systems is RHF.

The final example corresponds to a calculation of vibrational harmonic frequencies of the ammonia molecule.

Test run on ammonia     <------------------- your comment (ignored by Aces 2) 
N                       <------------------- Z matrix 
H 1 hn2                 <------------------- Z matrix 
H 1 hn3 2 hnh3          <------------------- Z matrix 
H 1 hn4 3 hnh3 2 dih4   <------------------- Z matrix 
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hn2=1.0272884788        <------------------- value of hn2 
hn3=1.0272258373        <------------------- value of hn3 
hn4=1.0272884788        <------------------- value of hn4 
hnh3=103.5344646668     <------------------- value of hnh3 
dih4=-107.7934123471    <------------------- value of dih4 
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REFERENCE=RHF,SCF_EXPSTAR=1,DROPMO=1,VIB=FINDIF <---- job control parameters 
SPHERICAL=ON,MEM=200000000,SCF_CONV=12,SCF_MAXCYC=300,CC_CONV=9)     <---- job control parameters 

The calculation uses the CCSD(T) method (CALCLEVEL=CCSD[T]) and the cc-pvdz basis set (BASIS=CC-PVDZ). VIB=FINDIF means that the force constant matrix is computed by finite difference of analytically computed gradients or energies using symmetry-adapted mass-weighted Cartesian coordinates. In this example, the second derivatives defining the force constant matrix are calculated by numerically differentiating the analytically computed gradients (first derivatives), which saves you a lot of computer time, since at least first derivatives are calculated analytically. The fact that you can do such things at the very high CCSD(T) level is a fairly unique feature of Aces 2. Notice the absence of *'s at variables used in Z matrix (geometry is not optimized in this example).

Aces 2 manual

A complete manual for Aces 2 is available from the web. Please click here for further details. The manual is available in the postscript and pdf formats.

Running Aces 2 jobs (on hbar)

After creating your input file with an editor (e.g. vi), save it under some name with extension of .inp (e.g. aces_file.inp ) and submit it to the queue. Command to send your Aces 2 job to the cem888 queue is:
aces2sub   -q   cem888   aces_file

Note: in the above line, your input file is assumed to be named aces_file.inp.
The output file will be called aces_file.out
You will also see the extra file OLDMOS_aces_file, which contains molecular orbitals for various restart calculations (you can erase this file, if you do not need it).

Checking the status of your job

You can use the command qstat -a to see the status of your and all other jobs. If you see a line with your name in it and some other job information, your job is in the queue (if the job status is R, the job is running).

To learn more about the NQS queue system running in the department, go here.