Perform a MD simulation of NaCl in water by running the input-file NaCl_in_water.inp.

Use VMD to calculate the Na-Cl distance for each frame of the trajectory. This can be done in the following way:

1. Load the trajectory with VMD
2. Select Extensions → Analysis → Radial Pair Distribution Function from the menu
3. Within the $g(r)$-dialog select Utilities → Set unit cell dimensions from the menu
4. Set the lengths a,b, and c to the value 12.413800, and click Set unit cell
5. Close the $g(r)$-dialog
6. Fold back periodic images by typing: pbc wrap -centersel “element Na” -center com -all
7. Select Mouse → Label → Bonds from the menu
8. Click successively on the Na and the Cl atom
9. Select Graphics → Labels… from the menu
10. Select Bonds from the drop-down on the top left
11. Go to the tab Graph
12. Click Save to store the distance-trajectory

Plot the obtained distance-trajectory. Does the dissociation occur? If it occurs, does the actual transition happens quickly ? Is dissociation a likely or rare event ? Do you expect an activation energy ?

NaCl_in_water.inp

&GLOBAL
  PROJECT NaCl-Free
  RUN_TYPE MD
&END GLOBAL

&MOTION
 &MD
   ENSEMBLE  NVT
   TIMESTEP  0.5
   STEPS   200000
   TEMPERATURE 350
   &THERMOSTAT
     &NOSE
       LENGTH 3
       YOSHIDA 3
       TIMECON 1000
       MTS 2
     &END NOSE
   &END
   &PRINT 
     &ENERGY
        &EACH
           MD 20
        &END
     &END ENERGY
     &PROGRAM_RUN_INFO
        &EACH
           MD 20
        &END
     &END PROGRAM_RUN_INFO
   &END PRINT
 &END MD
 &PRINT 
  &TRAJECTORY
     &EACH
        MD 20
     &END
  &END
  &VELOCITIES OFF
  &END VELOCITIES
  &FORCES OFF
  &END FORCES
  &RESTART_HISTORY OFF
  &END RESTART_HISTORY 
  &RESTART OFF
  &END RESTART
  &END PRINT
&END MOTION

&FORCE_EVAL
  METHOD FIST
  &MM
    &FORCEFIELD
      &SPLINE
        EMAX_SPLINE 300000.0
      &END
      &BEND
        ATOMS H O H
        KIND HARMONIC
        K [rad^-2kcalmol] 110.0
        THETA0 [deg] 104.52
      &END BEND
      &BOND
        ATOMS O H
        KIND HARMONIC
        K [angstrom^-2kcalmol] 900.0 
        R0 [angstrom] 0.9572
      &END BOND
      &CHARGE
        ATOM Na
        CHARGE 1.0
      &END CHARGE
      &CHARGE
        ATOM Cl
        CHARGE -1.0
      &END CHARGE
      &CHARGE
        ATOM O
        CHARGE -0.834
      &END CHARGE
      &CHARGE
        ATOM H
        CHARGE 0.417
      &END CHARGE
      &NONBONDED
        &LENNARD-JONES
          atoms O O
          EPSILON [kcalmol]  0.152073
          SIGMA   [angstrom] 3.1507
          RCUT    [angstrom] 11.4
        &END LENNARD-JONES
        &LENNARD-JONES
          atoms O H
          EPSILON [kcalmol] 0.0836
          SIGMA [angstrom] 1.775
          RCUT  [angstrom] 11.4
        &END LENNARD-JONES
        &LENNARD-JONES
          atoms H H
          EPSILON [kcalmol]  0.04598
          SIGMA   [angstrom] 0.400
          RCUT    [angstrom] 11.4
        &END LENNARD-JONES
        &LENNARD-JONES
          atoms Na Na
          EPSILON [kcalmol]  0.0469
          SIGMA   [angstrom] 2.7275
          RCUT    [angstrom] 11.4
        &END LENNARD-JONES
        &LENNARD-JONES
          atoms Na O
          EPSILON [kcalmol]  .08445
          SIGMA   [angstrom] 2.93
          RCUT    [angstrom] 11.4
        &END LENNARD-JONES
        &LENNARD-JONES
          atoms Na H
          EPSILON [kcalmol]  .0464
          SIGMA   [angstrom] 1.5637
          RCUT    [angstrom] 11.4
        &END LENNARD-JONES
        &LENNARD-JONES
          atoms Na Cl
          EPSILON [kcalmol]  .0838
          SIGMA   [angstrom] 3.63
          RCUT    [angstrom] 11.4
        &END LENNARD-JONES
        &LENNARD-JONES
          atoms Cl Cl
          EPSILON [kcalmol]  0.150
          SIGMA   [angstrom] 4.54
          RCUT    [angstrom] 11.4
        &END LENNARD-JONES
        &LENNARD-JONES
          atoms Cl O
          EPSILON [kcalmol]  .151
          SIGMA   [angstrom] 3.84
          RCUT    [angstrom] 11.4
        &END LENNARD-JONES
        &LENNARD-JONES
          atoms Cl H
          EPSILON [kcalmol]  .083
          SIGMA   [angstrom] 2.47
          RCUT    [angstrom] 11.4
        &END LENNARD-JONES
      &END NONBONDED
    &END FORCEFIELD
    &POISSON
      &EWALD
        EWALD_TYPE spme
        ALPHA .3
        GMAX 12
        O_SPLINE 6
      &END EWALD
    &END POISSON
  &END MM
  &SUBSYS
    &CELL
      ABC 12.4138 12.4138 12.4138
    &END CELL
     &COORD
O    1.1753544421905696E+01    4.4021851582586935E+00    7.9157840505153452E+00 H2O
H    1.2340708249225194E+01    3.6883791978006242E+00    8.1993630993470603E+00 H2O
H    1.1333172679938164E+01    3.8050318217272174E+00    7.2568637081413323E+00 H2O
O    1.1014668880096623E+01    7.3042865500623817E+00    1.5990673397287788E+01 H2O
H    1.0569187724590568E+01    6.6345975947947693E+00    1.5547591289605375E+01 H2O
H    1.1898462021703027E+01    6.9874187796347469E+00    1.6036139720330969E+01 H2O
O    1.2689782744905673E+00    6.6305310822204291E+00    3.8552255308181183E+00 H2O
H    1.6331787505516266E+00    7.5407334033566018E+00    3.8990549604441207E+00 H2O
H    2.0695006552397186E+00    6.0919818384977980E+00    3.4701014630706695E+00 H2O
O    1.4178648518519008E+01   -5.4114420257859823E+00    9.0104448041665517E+00 H2O
H    1.4017865457100729E+01   -4.5904322660861938E+00    8.5501233014882416E+00 H2O
H    1.3483940372104527E+01   -5.5149586247719489E+00    9.6651833370983109E+00 H2O
O    1.1452264597040871E+01    1.0887873649551166E+01    3.2084689203614567E+00 H2O
H    1.1967066565244300E+01    1.1445433261897549E+01    3.7649461013539907E+00 H2O
H    1.0557245919373200E+01    1.1324397817482820E+01    3.2777714519474994E+00 H2O
O    5.4034513877480865E+00   -5.6934982866713590E-01    4.1911517278163561E+00 H2O
H    4.5483481626988249E+00   -1.0111873129240894E+00    3.9370590485310837E+00 H2O
H    5.8745595810397493E+00   -1.3341026429777330E+00    4.5979862398760112E+00 H2O
O    1.0057227115948024E+01    1.6229149149924339E+01    2.3925996591412417E+01 H2O
H    9.2698383115214416E+00    1.6823858684663453E+01    2.4105928499738823E+01 H2O
H    9.7419675944524666E+00    1.5633504273481041E+01    2.3231028348851662E+01 H2O
O    8.8677965379732058E+00    1.1265135417657429E+01    9.3927083078931553E+00 H2O
H    8.0047959048088178E+00    1.0873622086214446E+01    9.1123875773689491E+00 H2O
H    8.9279753280405316E+00    1.1225261501792545E+01    1.0383859150647918E+01 H2O
O    3.4080063685919972E+00    3.8281480273536057E+00    5.2014798452536946E+00 H2O
H    4.2321572059400339E+00    3.3876157648413292E+00    5.0447755744929355E+00 H2O
H    2.8950992358414052E+00    3.6968963428074426E+00    4.3257317504719071E+00 H2O
O    3.2104267444392396E+00    1.0140965941598806E+01    5.4422954259256739E+00 H2O
H    2.7530338415002489E+00    9.8998848654428535E+00    4.5986562717830264E+00 H2O
H    2.4556531455595496E+00    1.0441077526316068E+01    6.0489660829709155E+00 H2O
O    4.0963537625725674E+00    8.0917539958074993E+00    1.0134372895799503E+01 H2O
H    3.3568409082389805E+00    7.7228723438249398E+00    9.6190434068097073E+00 H2O
H    4.3609077527930795E+00    8.7918074613791131E+00    9.5341819775764804E+00 H2O
O   -5.5665924947641816E+00    7.3067204927259235E+00   -1.9883598323724647E+00 H2O
H   -6.5034019372924075E+00    7.6053625026413805E+00   -2.0987994044233194E+00 H2O
H   -5.3150004199521055E+00    7.2870401654684125E+00   -2.9091914567841886E+00 H2O
O    1.1676278913686788E+01    1.5298249986393781E+01    1.6383563437817887E+01 H2O
H    1.2587464831334719E+01    1.5435371673523250E+01    1.6628396684857599E+01 H2O
H    1.1591655936254574E+01    1.5853475115631859E+01    1.5539570840387995E+01 H2O
O    1.4061976353495059E+01    9.2245551836285333E+00    3.3628338059328726E+00 H2O
H    1.3450288603772332E+01    9.9005997350888588E+00    3.6811276936530497E+00 H2O
H    1.4189484851779527E+01    9.4617482111957045E+00    2.4386940515991853E+00 H2O
O    4.0459889100093029E+00    6.5177362398102456E+00    2.5732744024062764E+00 H2O
H    3.5401823659550020E+00    6.8224242718743318E+00    1.8061354812594488E+00 H2O
H    4.3061858864345899E+00    5.6596188680600106E+00    2.2544873571934723E+00 H2O
O    5.3942555383779709E+00    5.9921077919598975E+00    5.5479964555191721E+00 H2O
H    4.5696452524535074E+00    5.5450869700159764E+00    5.3861090187122072E+00 H2O
H    5.8041847517531799E+00    5.4340702269751437E+00    6.2406501382283697E+00 H2O
O    1.1083204000766642E+01   -5.5817706946529055E-01    1.9012213049501533E+01 H2O
H    1.0766380933295238E+01   -1.5297161070578786E+00    1.9234395970879390E+01 H2O
H    1.0301075722148791E+01   -2.2202937914601956E-01    1.8534569531285435E+01 H2O
O    8.0791998553974889E+00    7.3510519348550423E+00   -4.3460713060718152E+00 H2O
H    7.6759201146623637E+00    6.6038372265123675E+00   -4.9207705506418193E+00 H2O
H    7.7374893085203249E+00    8.0604176451161393E+00   -4.9062736907587210E+00 H2O
O    9.0599466123812089E+00   -1.1429275580287841E+00    1.2359299045122484E+01 H2O
H    8.1731340512894715E+00   -8.4813525786179789E-01    1.2153183944704283E+01 H2O
H    9.3354403117752280E+00   -3.0344035057609919E-01    1.2782538396372816E+01 H2O
O    7.3128194079715705E+00    1.0087518663499242E+01    4.6982644114541596E+00 H2O
H    8.0618288813246686E+00    9.7202011976988612E+00    5.2055576656885707E+00 H2O
H    7.2561941364348446E+00    9.4520654638910369E+00    3.9300655501395521E+00 H2O
O    7.9081332415871142E+00    1.3493631056974145E+01   -1.7023111105913979E+00 H2O
H    7.9296786531697769E+00    1.2737626146720082E+01   -2.3310520486375612E+00 H2O
H    8.8258690050704462E+00    1.3833681600410728E+01   -1.8106172707798294E+00 H2O
O    3.0343124639160681E+00   -5.1228535011701286E+00    2.0672656222212285E-01 H2O
H    3.6229508004737765E+00   -5.0138795773847775E+00   -5.4302739923341814E-01 H2O
H    2.4430790352456935E+00   -4.4202075922270847E+00    3.0522044152506863E-02 H2O
O    6.1403349808958954E+00    1.3553394843140385E+00    3.5842881823535444E-01 H2O
H    6.8199298055993873E+00    1.2490493021132034E+00   -3.7837775822664221E-01 H2O
H    5.4136904105251489E+00    7.7533952254521210E-01   -2.0200981294157712E-02 H2O
O    1.1818413215892830E+01    6.0342992643590794E+00    1.0161892222232515E+01 H2O
H    1.1984376256547076E+01    5.5829933767316451E+00    9.3073360179197255E+00 H2O
H    1.1359766709069046E+01    5.3662463571587269E+00    1.0616419288216939E+01 H2O
O    2.0056876408425651E+01    1.4884394953405629E+01    1.4785031476074208E+01 H2O
H    2.0914912760107462E+01    1.4685896617430362E+01    1.4355413941592094E+01 H2O
H    1.9453366228760853E+01    1.4584456213825597E+01    1.4072600004011722E+01 H2O
O    1.4255904314186182E+01    2.1756635286452664E+00   -2.0579711479072640E-01 H2O
H    1.3805349503679688E+01    2.9528386128226822E+00   -4.8295360444351881E-01 H2O
H    1.3569123093943860E+01    1.6551351670404930E+00    2.5853592700899408E-01 H2O
O    7.6086778925713991E+00    5.1699928912468014E+00   -4.9638488295799893E-01 H2O
H    6.7781094300338305E+00    4.7946702112099135E+00   -5.7099171112346547E-01 H2O
H    7.3607191780882069E+00    5.9446369058096078E+00   -1.1349785326398023E+00 H2O
O    1.2020909502195277E+01   -1.7339290247423964E-02    9.4954974980296427E+00 H2O
H    1.1610474491815115E+01   -5.8818398715592990E-01    8.8344295516358979E+00 H2O
H    1.2553354307793303E+01   -6.6079275446538310E-01    9.9480054031386871E+00 H2O
O    1.6125272725360077E+01    1.4144118398901252E+01    1.0018485667325464E+01 H2O
H    1.5358446740855484E+01    1.4240179363530874E+01    1.0535697576993389E+01 H2O
H    1.6448807629032782E+01    1.3331588379115230E+01    1.0446181193701090E+01 H2O
O    2.3784433487149315E+00    1.1076368066157427E+01    8.7625696673092115E+00 H2O
H    2.1625304504587910E+00    1.0952073635783481E+01    9.7050954143082162E+00 H2O
H    2.0943392125095457E+00    1.0240369700452140E+01    8.3110192332165411E+00 H2O
O   -2.6202486540065455E+00    1.4011749466336040E+01    1.3270861019058238E+01 H2O
H   -1.7969706446069031E+00    1.3789345701846116E+01    1.3728013603660095E+01 H2O
H   -2.2451970406009290E+00    1.4582611904820402E+01    1.2604464854929647E+01 H2O
O    6.2324420266564085E+00    3.2029433865186432E+00    9.3624276034988796E+00 H2O
H    5.5245049044418595E+00    2.5909899487287613E+00    9.1683914888494868E+00 H2O
H    6.9326197318002958E+00    2.5510489529092562E+00    9.5829330178095926E+00 H2O
O    4.7056900888016964E+00   -2.1740031489115283E-01   -4.7455853617226955E+00 H2O
H    3.8419378351717626E+00   -4.0825662269384883E-01   -4.2322475898066978E+00 H2O
H    4.3556294121150945E+00   -6.8993416251599368E-02   -5.6172218051143767E+00 H2O
O    7.9052074989079832E+00    9.2948507676364112E-01    6.8291165660776105E+00 H2O
H    7.8329518120522037E+00   -7.3239505544300101E-02    6.8912772475034485E+00 H2O
H    7.1525080724220409E+00    1.0968384122968011E+00    6.2602612138667606E+00 H2O
O   -1.0398132450870442E+01    2.7421665494827967E+00    7.9771104768784520E+00 H2O
H   -1.0118440415027528E+01    1.8744659613464276E+00    7.6017037030346311E+00 H2O
H   -1.0281068420389072E+01    3.3134252506494537E+00    7.2268217324361457E+00 H2O
O    1.7533809170986110E+01    8.3996884769277145E+00    7.0775230417456161E+00 H2O
H    1.6717092384419313E+01    8.7623151811233821E+00    6.7539563539362222E+00 H2O
H    1.7543220685207306E+01    7.5975629140922765E+00    6.6031835390524032E+00 H2O
O    9.5953872749122588E+00    8.8268858183947163E+00    5.4382850332669426E+00 H2O
H    1.0238607616030258E+01    8.4651601433012935E+00    6.0669495439702921E+00 H2O
H    9.9642126418558927E+00    8.3861554514842460E+00    4.5985338458206115E+00 H2O
O    8.7359549409803368E+00    1.1920084550572563E+01    1.5852925009243505E+01 H2O
H    8.0301244117232340E+00    1.1463505274064429E+01    1.6306205471860146E+01 H2O
H    8.4028868462495421E+00    1.2798595199963700E+01    1.5745710868385185E+01 H2O
O    1.1342387483264285E+00    5.2005653993259084E+00    1.2366711127094838E+01 H2O
H    1.1431529635020097E+00    5.1320701266105537E+00    1.1414135555772207E+01 H2O
H    1.8795654384061717E+00    5.8743639708810225E+00    1.2435944020993762E+01 H2O
O    4.3425048054329363E+00   -3.8372902380130947E-01   -6.8811389491354846E-01 H2O
H    4.9653001666371264E+00   -1.1389448951649650E+00   -7.2877424200227259E-01 H2O
H    3.4795887915173225E+00   -7.7707860793195005E-01   -7.2294198067867210E-01 H2O
O    6.1470830049255065E+00    1.0085545639361571E+01    1.2268736915938019E+01 H2O
H    6.5254072780528931E+00    9.2877004313627101E+00    1.2081645015830070E+01 H2O
H    6.1233735619293537E+00    1.0012722305828664E+01    1.3215459072130194E+01 H2O
O    6.6165176287786709E+00    1.0529619266394285E+01    8.1992767508908582E+00 H2O
H    5.9988949867397610E+00    9.7988783921300175E+00    7.8716578752856874E+00 H2O
H    6.1011758707194499E+00    1.1339592595597649E+01    8.1245330556548261E+00 H2O
O    8.7448930318205207E+00    4.2035778229574090E+00    1.6667592832738887E+01 H2O
H    9.6172437182814239E+00    4.0012818436346835E+00    1.7026462880666656E+01 H2O
H    8.5879634837153418E+00    3.5408621470564983E+00    1.5950016180164910E+01 H2O
O    9.5857210543430735E+00   -4.3492649059459136E+00    1.0605138978330569E+01 H2O
H    8.7011778178526846E+00   -4.3054052892968100E+00    1.0155639446375634E+01 H2O
H    9.8328305198610977E+00   -5.2662332273982075E+00    1.0325404642237823E+01 H2O
O    7.1655754815424828E+00    4.8164058031273917E+00    6.9827991623818564E+00 H2O
H    6.9362457515784772E+00    4.1932819035984634E+00    7.6424112374177593E+00 H2O
H    7.6766494125251219E+00    4.2500051222557786E+00    6.3821210756773006E+00 H2O
O    4.8297972570762884E+00    4.2070042207196598E+00    1.1472942891352414E+01 H2O
H    5.2224983419581656E+00    3.8616217919542937E+00    1.0624799108046785E+01 H2O
H    3.8202638973321665E+00    4.1557641669173115E+00    1.1130561361855788E+01 H2O
O    6.1141281181639009E+00   -3.9160509004418516E+00    2.2361959985724997E+00 H2O
H    6.6741010314616558E+00   -4.6633655391585531E+00    2.4374748071535737E+00 H2O
H    5.1417813696946197E+00   -4.2737431164787880E+00    2.4860458939795342E+00 H2O
O    1.2422237951227883E+01    9.0346188032113839E-01    1.4858124935094497E+00 H2O
H    1.2774907114847005E+01    7.9492905489321919E-01    2.3876055579074382E+00 H2O
H    1.2383980110238154E+01    1.2639047505481145E-02    1.1711072142709946E+00 H2O
O   -1.9573950131095728E+00    2.6547233003600650E+00    6.3264685386946971E+00 H2O
H   -1.5890515349546790E+00    2.5049832646796166E+00    5.4377691277090836E+00 H2O
H   -2.6601680989277559E+00    2.0455377964092993E+00    6.3910371192140198E+00 H2O
O   -5.1746639502257485E+00    6.3268173165266930E+00    3.4022453265951325E+00 H2O
H   -5.8538826533083252E+00    6.0630475658559417E+00    4.0593847493701283E+00 H2O
H   -4.5456200014420274E+00    5.5948800178610094E+00    3.6466245011307188E+00 H2O
O   -1.7301550732454403E+00    9.4433133588285223E+00    8.2730143525629956E+00 H2O
H   -2.3588285739544199E+00    8.7002435560310936E+00    8.3843236064855855E+00 H2O
H   -2.1404889687710758E+00    1.0047127016482493E+01    8.9211555005887586E+00 H2O
O    9.0552712375692934E+00    6.5294172265623143E+00    1.3742439694437869E+00 H2O
H    8.3516076276067128E+00    6.3289151269823343E+00    2.0304907300642321E+00 H2O
H    8.6528091280456980E+00    6.1831779653637149E+00    5.4298333174784219E-01 H2O
O    4.5813760239127364E+00    4.1843345295343770E+00    1.6253526169022317E+00 H2O
H    5.3727323765311770E+00    3.6298864387852703E+00    1.7138976863611635E+00 H2O
H    4.6395747674616947E+00    4.3116322589753313E+00    6.3887219177749843E-01 H2O
O    1.2947678437786887E+00    3.0271301953495872E-01    6.7378909919380270E+00 H2O
H    3.1428367266724405E-01    4.5252218318749998E-01    6.7605145342793884E+00 H2O
H    1.4651549989733721E+00    4.4724440682281402E-02    7.6184299786305614E+00 H2O
O    2.2801010341157997E+00    4.5384374803766505E+00   -2.4223048356780224E+00 H2O
H    2.0734054267726179E+00    3.6882567015458987E+00   -2.9666204618216470E+00 H2O
H    2.5231047554518509E+00    5.2235789091310938E+00   -3.1134597962105883E+00 H2O
O    3.7181632387798422E+00    1.3194671983555407E+01    2.1247302219660935E+00 H2O
H    4.6221675287950585E+00    1.3097092431390625E+01    1.7939883243389010E+00 H2O
H    3.2943497598348452E+00    1.3194908989088310E+01    1.2280237106837808E+00 H2O
O    8.8760226994556335E-01    9.0819224935268252E+00   -4.9139340386609893E+00 H2O
H    6.5645671723934040E-01    8.2903238990744885E+00   -5.4378003156474533E+00 H2O
H    5.8843124393715890E-02    9.2202134104728284E+00   -4.4441892901661255E+00 H2O
O    1.1597624822673641E+01    1.6904970546553898E+01    1.8174920862357313E+00 H2O
H    1.2296467925610532E+01    1.7299711348881257E+01    1.2631420756029890E+00 H2O
H    1.0851674042026399E+01    1.6978470962780285E+01    1.1636392443535732E+00 H2O
O    1.3687809934453169E+01    1.2505476198613239E+01    3.9130051114462949E+00 H2O
H    1.4539114519746876E+01    1.2552958854294646E+01    3.5281360273279936E+00 H2O
H    1.3943283510045202E+01    1.2638239442171317E+01    4.8024112307295050E+00 H2O
O   -2.0127124384156674E+00    1.4456792042391635E+01    9.3689965302971068E+00 H2O
H   -1.2613367153937676E+00    1.3868330798915297E+01    9.5235783609143425E+00 H2O
H   -2.1313935694969701E+00    1.4494082421039327E+01    8.3588717975939772E+00 H2O
O    5.9282480309534415E+00    2.1805080018332679E+00    4.7215454301010942E+00 H2O
H    6.4216163069448253E+00    2.4503801200770838E+00    3.8999417372827963E+00 H2O
H    5.5064601702213665E+00    1.3017508101133179E+00    4.5015046675505532E+00 H2O
O    1.3855624950094682E-02    6.7674752704789931E+00    6.4172582115352652E+00 H2O
H   -3.9884540327593410E-01    5.9879627341341282E+00    6.8897045580221494E+00 H2O
H    1.6576784524421465E-01    6.4353752097379919E+00    5.5228784846639938E+00 H2O
O    1.4501812945221763E+01    3.3923060631855058E+00    3.0756235664424216E+00 H2O
H    1.3706746681864210E+01    3.4193537022149547E+00    2.5497917586387699E+00 H2O
H    1.5269466984949403E+01    3.1093971613675038E+00    2.5273427220944495E+00 H2O
Na    1.0978482003279533E+01    9.1862595374996374E+00    1.3069121663365122E+01 NAP
Cl    1.3489457703231567E+01    1.0346547591020910E+01    1.2149103773398551E+01 CLM
     &END COORD
     &COLVAR
       &DISTANCE
         ATOMS 190 191
       &END DISTANCE
       &PRINT
       &END
    &END COLVAR
    &TOPOLOGY
      CONNECTIVITY GENERATE
      &GENERATE
        BONDLENGTH_MAX 7
      &END
    &END
  &END SUBSYS
&END FORCE_EVAL